Gardening in March – 3. Planting

Gardening in March – 3. Planting

Gardening in March – Planting in March

The garden is coming alive in the first months of spring, with all the colors of the spring bulbs bursting into bloom. There are plenty of flowers to be found in the gardens, including Crocus, Daffodils, and the scented Narcissus.

Feel like it’s too early for you to think about your spring garden? Not even close, because March is the prime time to plant cool-weather veggies made for earlier spring weather that can withstand the cool, early days of spring. In addition, it is a great time to sow a variety of seeds so they’ll be ready for planting earlier in the year.

If you are wondering what vegetables can survive the cooler temperatures in March, you might be amazed at the number of vegetables that are hardy enough to survive the cold, but if you start planting now, you’ll have homegrown, freshly harvested food in no time at all.

In March, weather conditions can vary widely and can make gardening forecasting less accurate. The weather in March can be warm and brisk, or it can be cool and frosty. Weather will influence the degree to which the soil has warmed to the appropriate temperature for planting.

House & conservatory plant

Watering

As plants start to grow, increase watering gradually but let the compost dry out slightly between waterings. If the compost feels moist to the touch then watering is not necessary, but if it feels dry, then water. Use a watering can with a long spout, fill the plant container with water, and let it drain away, but do not put water on the top of any plant as the foliage and crown may rot.

Feeding

Feed plants if they are growing actively. For healthy foliage add a slow-release fertilizer or a high-nitrogen liquid feed when the compost is damp.

Light and aspect

Move plants from south-facing windowsills in sunny weather or they will get too hot and dry. As the days get longer move the plants in flower, such as African Violets, to west-facing windowsills.

Maintaining healthy foliage

Cut back neglected plants (except palms) to healthy buds to encourage fresh foliage. Cut back ferns to their crowns, water well, and leave them in light shade. They should soon produce fresh new fronds.

Wipe glossy-leaved plants with a leaf shine and remove dead leaves.

Flowering plants

Feed with either a high-potash feed formulated specifically to promote flowering in house plants or, as a good, cheap alternative, tomato fertilizer. Give azaleas and camelias an ericacaceous feed designed especially for acid-loving plants.

Take cuttings of abutilons and Tibouchina semidecandra from now until September. Insert the young shoots in sandy compost and keep them at a temperature of about 20°C (70°F) until rooted.

Indoor bulbs and corms

Keep gloriosas warm and increase watering as growth restarts. Provide trellis or stakes for the new shoots to grow up. Plant out pot-grown bulbs as soon as they finish flowering in March. Plant hippeastrums for late spring flowering in pots. Keep them in a warm, humid atmosphere and water sparingly until the buds appear.

Climbers and feature plants

Cut out weak or diseased shoots, tie in any growth that needs support and clear away dead leaves from the surface of the compost. Cut abutilons back hard (you can use the prunings for cuttings) but do not prune bottlebrushes (Callistemon).

Bromeliads

Water freely with rainwater if possible, but let the compost dry between waterings. Avoid wetting the neck of the plant as this could encourage rotting. Put water in the urn formed by the rosette leaves, but change the water now and then. Feed with a liquid feed, diluted to a quarter or third of the normal strength, once a month.

Mist air plants with a foliage feed once a month, and continue to mist with water only, once or twice a week.

Cacti and other succulents

Stand forest succulents, such as Christmas and Easter cacti, on a tray of moist pea gravel, to provide extra humidity if they are in a dry room.

Towards the end of March move cacti and succulents kept dry over winter to a warm room, and water them. Fill the pots to the brim with water and repeat, until water flows from the drainage holes. Let the compost dry out before watering again.

Pot on cacti if they begin to look too large for the pot or growth is poor or slow for that species.

  1. Repotting cacti can be painful, but this technique makes it less so. Ensure the rootball is loose by pushing a pencil through the drainage hole.
  2. Make a ‘handle’ from a strip of thin card and lift the plant from the pot. Loosen the compost around the roots if it is compacted.
  3. Repot the cactus in a pot one size larger. Trickle in cactus compost around the edge. Tap the pot on a hard surface to settle the compost around the roots.
Orchids

Water so that the compost is moist but not soaking wet. Keep orchids without swellings at the base of their leaves (psuedobulbs), such as moth orchids (Phalaenopsis) and slipper orchids (Paphiopedilum), constantly moist but not waterlogged. Orchids with pseudobulbs, such as cambriam hybrids, cymbidiums, and cattleyas, are more drought tolerant and can be allowed to dry out slightly between waterings.

Purchase flowering cambriam hybrids and cymbidiums if not yet done. It is best to buy orchids from a specialist nursery or garden center.

Rhododendrons & azaleas

Gardening in March - 3. Planting

Planting in March

Continue to prepare the soil and start planting in March if warm weather arrives.

Unlike some shrubs, it is quite usual to buy rhododendrons and azaleas in flowers. Between them, azalea and rhododendron flowers cover almost every color in the spectrum so you should be able to find the color you want for your garden.

There is also a huge range of varieties available, from dwarfs to types which, in time, grow into multi-stemmed trees. When choosing and planting rhododendrons and azaleas, take into account the ultimate height and spread of the varieties chosen, so that the plants do not become too crowded later on.

Care needs to be taken when watering and whenever possible, use rainwater. Newly planted rhododendrons and azaleas are very slow t root into the surrounding soil, so make sure that both the rootball and ground are soaked before planting in March and check new plantings regularly to see if they need watering.

Layering

Assess which established rhododendrons would be suitable for propagation. If you want to propagate by layering, prune some lower branches now to encourage fresh shoots suitable placed for layering in 18 months’ time.

Semi-ripe cuttings of azaleas

Pot up semi-ripe azalea cuttings taken last year into individual pots and grow on until the autumn.

Growing in containers

If you want to grow rhododendrons or azaleas but have alkaline soil, growing them in a container is often the most satisfactory solution. Both make good container plants. Even large specimens can be kept in good condition for a number of years, but there are also many dwarf hybrids that are excellent if you are short of room.

Choose a permanent container at least 15cm (6 in) in diameter larger than the rootball or the pot the plant is supplied in. Add a good quantity of crocks or stones for drainage and fill the container with lime-free (ericaceous) compost.

Position the plant carefully at its original level and firm the compost around the rootball. Water well with rainwater if available and feed with a sequestrate-based fertilizer. Keep the compost moist.

If you are growing a large specimen you may need to top-dress the plant each year; smaller plants can be repotted into containers one size larger.

Rock plants

Controlling weeds

As the surface of the soil becomes drier, hoe lightly and carefully around the plants to remove newly germinated weed seedlings, taking care not to disturb any bulbs that may be emerging. An onion hoe or a three-tined cultivator is ideal.

Replenish any top dressing disturbed during this work with fresh stone chippings or gravel. Fork out weeds, such as annual grasses and groundsel, and shake off any excess soil. Carefully remove any perennial weeds, such as dandelion, ground elder, and creeping buttercup, either with a hand fork or a trowel, ensuring that all the roots are removed.

Germinating seeds

While gardening in March you need to watch carefully for signs of germination in trays of seed placed outside for weathering. Replace any of the top dressing that has been washed away with sand or fine chippings. Once signs of growth appear, move the choicer or slower growing plants to a cold frame or unheated greenhouse before pricking out. Take care at this stage not to allow trays to dry out, but do not overwater.

Planting in March

Plant rock plants from the nursery or garden center as soon as possible after purchase. If they have come by post and the weather is cold, pot them up and store them in an unheated greenhouse or cold frame.

Add leafmould or garden compost mixed with a general fertilizer or bonemeal to the planting area at the rate recommended by the manufacturer. A nutrient-enriched peat or peat substitute eliminates the need for any additional fertilizer. Monitor the spread of plants so that slow-growing rock plants are not crowded out by quick-growing neighbors.

Division

Dividing clumps of plants is a good way of increasing stock and rejuvenating those which have become old and woody in the center. It is also a way of saving live portions of plants that have suffered from dieback in wintry weather.

Capering plants which root as they travel along, such as androsaces, campanulas, raoulias, and some saxifrages and sedums, respond well to this treatment, as do some other taller plants. With early-flowering plants, it is better to wait until after flowering before dividing.

Lift the plants out of the soil, trim them and cut out dead or unhealthy parts. Then pull the clump gently apart into portions about (2.5-5 cm (1-2 in) across. Dig over the soil where the old plants were and add bonemeal and leafmould before replanting the divided portions.

Gentiana sino-ornata, one of the most beautiful alpine rock plants, should be divided every other spring. Prise the root thongs apart and replant them in moist, humus-rich soil.

Potting uproot cuttings

Check root cuttings taken in February that have been growing over the past month. Plant these up into small pots using John Innes No. 1 potting compost when they have produced a few leaves and have a well-developed root system.

Lewisias

Start watering lewisias that have been kept in dry conditions over winter.

Controlling pests

Check rock plants for vine weevil and treat as necessary.

Trees, shrubs & hedges

Planting new trees and shrubs

As long as the soil is not frozen or waterlogged, planting in March also includes shrubs and all types of hedges. Complete the planting in March so that the bare-root specimen will be established before the summer.

Feeding

Apply a general fertilizer such as Growmore to all trees and shrubs according to the manufacturer’s instructions.

Protection from late frost

When sharp frosts are forecast, protect new leaves, shrubs, and trees from damage by wrapping them in horticultural fleece or netting. The shrubs most at risk are the silver or grey-leaved plants, such as cistus, halimum, caryopteris, and the Californian poppy, and those whose native habitat is sheltered woodland, for example, Japanese maples, hydrangeas, camellias, crinodendrons, and pieris.

Many of the most ornamental trees and large decorative shrubs which have become extremely popular in gardens originated in warmer climates and need some cosseting. These include Cytisus battandieri, ceanothus, foxglove tree, and eucryphia. If you want to grow any of these trees and shrubs, you should start with some planting in March.

Layering

Many shrubs with low branches can be layered now either into pots or directly into the soil at the base of the plant.

Choose low-growing shoots from the previous season’s growth. If you are layering the branch directly into the ground, prepare the soil by forking it over. Dig in some garden compost to help retain moisture and add a handful of bonemeal.

With many species, wounding the stem slightly encourages rooting. Remove a very thin layer of bark from the reverse side of one of the buds on the shoot that is to be layered and apply a little rooting hormone to the wounded area. Bury the layer, peg it down and water occasionally. By October the new plant can be removed from its parent and potted up or planted in its final growing position.

Hardwood cuttings

Most hardy shrubs will still propagate well from hardwood cuttings taken this month. Insert these cuttings in a trench in the garden and leave them undisturbed, apart from the occasional watering in dry weather, until the autumn.

Increasing ground cover

Dig up, divide and replant the self-rooted shoots of quick-spreading shrubs and sub-shrubs, such as rose of Sharon (Hypericum calycinum) and periwinkle (Vinca), to increase the amount of good cover.

Propagating from seed

Continue to sow seeds in March. Sow seeds of shrubs and trees into pots of compost, including seeds that are of a dry nature or have been stratified over winter. Germinate at a soil temperature of 13-18°C (55-65°F) in a heated propagator.

Pot on seedlings sown last summer which have been over-wintered in frost-free conditions.

Semi-ripe cuttings

By the end of the month, semi-ripe cuttings taken last spring and summer should have developed good roots. Pot these on to individual pots. Don’t worry if the leaves have dropped off (even from evergreens) as new shoots will form from the buds at the base of the cutting.

Leaf bud cuttings

Camelias can be increased by leaf bud cuttings. Keep the cuttings moist, warm and shaded and they will normally be rooted and ready to pot by late summer.

Root cuttings

Shrubs such as Romneya coulteri can be increased by taking new root cuttings. When new growth appears, remove the cuttings, pot on, and keep them watered in a sheltered part of the garden for planting out next spring.

Last spring’s root cuttings will have matured into new plants by now. Plant these out in their final growing positions.

Pruning in March

Start to prune spring-flowering shrubs over three years old, as they finish flowering, using the one-third method.

Early in the month prune the shrubs that produce their best show on vigorous new wood. Cut them back hard to within a few inches of the main framework. The hard pruning is best done just as the leaves begin to open, but before they are fully formed. It is most successful if done annually to prevent the plants from becoming hard and woody.

Shrubs that respond especially well to this method are Buddleja davidii, caryopteris, ceratostigma, Hydrangea paniculata, lavatera, leycesteria, perovskia, santolina and senecio.

Shrubs grown for their decorative stems, such as Cornus alba and C. stolonifera varieties and certain eucalyptus species, should be hard pruned in the same way.

Frost damage

Remove the ends of shoots on shrubs damaged by frost, even if they should not be pruned now. This prevents the spread of disease and further dieback.

Hedges

Planting in March

Continue with more planting in March. You can plant bare-root and container-grown hedging plants, including evergreens, and feed both newly planted and established hedges with Growmore, following the manufacturer’s instructions.

Cutting back

Cut back newly planted deciduous hedges of leggy plants, such as hawthorn and privet, to 15 cm (6 in) from the ground. In their second winter cut them back hard again by half the previous season’s growth. This hard pruning promotes good, bushy growth at the base.

Hedging plants that are naturally bushy at the base, such as beech and hornbeam, should be cut back by one-third. Conifer hedges are trimmed in late summer.

Reshape overgrown laurel and privet by the three-year method used for yew hedges.

Removing seedlings

Watch for brambles, ash, holly, and sycamore that have been self-grown by birds using the hedge as a roost or resting place, and dig them out.

Growing trees and shrubs from seed

Some trees and shrubs grow relatively quickly from seed. Specialist suppliers will be able to provide a larger range. Always read the instructions on the seed packet or in the catalog before planting as some trees and shrub seeds need warmth for rapid germination, while others require a cold spell. Seeds also vary considerably in how quickly they germinate, so don’t be in a hurry to discard the pots.

Climbers & wall shrubs

Choosing plants

When the severe weather has passed you can start planting in March. Plant all hardy climbers and wall shrubs. Wait another month for less hardy types.

Choosing the right plant for the right position needs careful thought to avoid disappointment. Check on the plant’s ultimate size – not only its height and spread but also the space it needs to flower to its full potential. Also, consider whether a plant will interfere with doors and windows when it has reached its ultimate size.

North and east-facing walls and fences that are exposed to frost and cold winds require plants that can tolerate such conditions. There are a good number of shrubs and climbers, including roses, that will flourish on the north and east-facing walls and, conversely, a number that requires the extra warmth and shelter that a south-west or south-facing wall provides.

Providing plant supports

If not already done, fix additional trellis or support wires in place, and tie new stems to them as climbing plants grow.

Feeding in March

It is important to feed climbers and wall shrubs as they need to cover large areas of space quickly. Apply a balanced, slow-acting general fertilizer in the spring around all established plants, and also when planting any new shrub or climber.

Frost protection

Continue to protect any tender climber or wall shrub in case of damaging spring frosts at night (particularly when a frost warning has been given). On more hardy plants it may now be safe to remove any frost protection that you have in place unless there is a sudden drop in temperature.

Annual climbers

Sow seeds in March if not already done.

Hardwood cuttings

Cuttings of hardy climbers such as climbing bittersweet (Celastrus orbiculatus), jasmine, honeysuckle and Russian vine (Polygonum baldschuanicum, syn. Fallopia baldschuanica) usually do well if they are taken this month. Choose stems from wood grown the previous year.

Layering

Dig up layers made last summer, which should now be well rooted, and cut them away from the parent plant. Pot the new plants into 15 cm (6 in) pots to grow on until the autumn or plant them out in their final growing positions. While gardening in March, prepare the ground well.

Pruning in March

Early-summer flowering clematis only requires a light trimming over. Remove shoots now that show no live buds. Cutting away too much live growth will mean cutting away future flowers.

Clematis which bloom from July to August onwards produces their flowers on new growth. These should be cut back hard to within 8-15 cm (3-6 in) of last year’s growth. This may leave little more than a stump. Prune before the leaves develop fully, but do not worry about cutting away fat leaf buds – plants will easily grow to 2.5 m (8 ft) or more in a season.

  1. Clematis that flower from mid-summer onwards, on shoots produced this year, should be pruned annually – in late winter or early spring. Cut all the shoots back to about 23-60 cm (9-24 in) above the ground.
  2. Cut back to just above a pair of buds – the exact position is not critical. Try to ensure this is done before the new leaves are fully opened, in the first half of March, if not before. New shoots will soon be produced.
Pruning other climbers

Treat old shoots of golden hop (Humulus lupulus ‘Aureus’) in the same way as late-flowering clematis to induce strong new basil growth – it can grow more than 5.5 m (18 ft) in a season and produce good foliage and flowers.

Wall shrubs and tender perennial climbers that flower on new wood should be cut back hard as soon as strong growth begins.

Watering and mulching

If climbers and wall plants show signs of drying out, give them a thorough watering and mulch them.

Choosing a climber

Climbers for a north or east-facing wall

  • Clematis: Most clematis will grow in shade, and those with delicate colorings, such as the popular Nelly Moser, generally look better in a shady spot as the flowers tend to fade in strong sun.
  • Hedera (ivy): All ivies do well, and there are many forms of the common H. helix, but try the attractively variegated large-leaved H. colchica ‘Dentata Variegata’ too. Ivies have the bonus of being evergreen.
  • Hydrangea petiolaris (climbing hydrangea): This self-clinging climber can be grown up a tree or against a wall. The white flower heads appear in June and July.
  • Lonicera japonica (Japanese honeysuckle): Grow the variety ‘Halliana’ for its scent and profuse whitish-yellow flowers L japonica. ‘Aureoreticulata’ has yellow-veined netted evergreen or semi-evergreen leaves.
  • Parthenocissus: The Boston ivy (P. tricuspidata) and Virginia creeper (P. quinquefolia) grow very tall. P. henryana is less vigorous and ideal for a shady wall. All have good autumn color.
  • Vitis (ornamental vine): Grow these for foliage effect. V. vinifera “Purpurea’ has purple-claret leaves, turning wine-purple later. V. coignetiae has much larger leaves, with good autumn color.

Climbers for a south or west-facing wall

  • Actinidia kolomikta (kolomikta vine): Large, heart-shaped leaves splashed cream and pink.
  • Aristolochia macrophylla (Dutchman’s pipe): Vigorous twiner with large green leaves and flowers.
  • Campsis radicans (trumpet vine): Woody-stemmed root climber with red to orange trumpet-shaped flowers.
  • Clematis: These popular plants like their roots in shade. The flowers tolerate full sun although some may lose color.
  • Lonicera x brownii ‘Dropmore Scarlet’ (scarlet trumpet honeysuckle): Produces tubular scarlet flowers in mid-summer.
  • Passiflora caerulea (passion flower): Fascinating blue flowers, but needs a sheltered position.
  • Vitis (ornamental vine): Grown for its ornamental leaves, those of V. coignetiae being particularly large.
  • Wisteria: Popular twining climbers with long racemes of lilac to purple flowers. There are also white forms.

Climbers for a pergola

  • Clematis: Some large-flowered varieties will cover pillars, but choose a suitable species such as C. montana if you want cover across the top of a pergola too.
  • Jasminum officinale (jasmine): A twiner with fragrant white flowers in summer.
  • Lonicera periclymenum (honeysuckle): Very fragrant. ‘Belgica’ flowers early, ‘Serotina’ late, ‘Graham Thomas’ is also widely available and flowers profusely. L. japonica varieties are suitable too.
  • Roses: Climbing, rambler, and pillar roses are all suitable, and there are many varieties.
  • Vitis (ornamental vine): Foliage plants with sometimes spectacular autumn color.

Self-clinging climbers for a wall

  • Hedera (ivy): Will reach to the top of very tall walls in time, but can be pruned back to size. Evergreen.
  • Hydrangea petiolaris (climbing hydrangea): Naturally grows up trees, but will cover a wall.
  • Parthenocissus (Boston ivy, Virginia creeper): Foliage plants for high walls. Good autumn color.

Annuals & biennials

Gardening in March - 3. Planting

Sow seeds in March

Complete the sowing of annual climbers early this month to allow the maximum growing time. As well as those listed last month, also sow purple bell vine (Rhodochiton atrosanguineum) which, although a perennial, can be treated as an annual; black-eyed Susan (Thunbergia alata); and canary creeper (Tropaeolum canariense, syn. T. peregrinum). Soak the seeds of the black-eyed Susan and canary creeper overnight before sowing to help the seeds absorb water and germinate faster.

Preparing seedbeds

Continue to prepare seedbeds for outdoor sowing, provided the soil is dry enough. Cover with netting to prevent cats from fouling the area.

Transplanting hardy annuals

Once the milder weather arrives, remove cloches from overwintered hardy annuals and start to move the plants to their final flowering positions in the garden. When transplanting, thoroughly water the plants in and protect vulnerable specimens from slugs and snails.

Hardy annuals overwintered under cloches or in frames can now be planted into their flowering positions. Water, then lift with a hand fork or trowel.

Replant with a little delay as possible, making a hole large enough to take a rootball with minimal disturbance. Firm in well to remove large pockets of air.

Water thoroughly. This will help to settle the soil around the roots as well as prevent wilting. Water as often as necessary until the plants are growing well again.

Sow seeds in March

Most bedding plants should be sown while gardening in March, either in a heated propagator in the greenhouse or on a warm windowsill. Exceptions are slow-maturing plants that need to be sown earlier, and fast-maturing plants which can be left until May. Follow instructions for sowing fine seed for busy lizzies, mimulus, petunias, and nicotiana.

Some seeds such as nemesias, pansies, mesembryanthemums, and verbenas, germinate best in darkness, so cover the containers in which they have been sown with brown paper or foil. Always look on the seed packet to check the conditions required for germination.

Instructions on seed packets may give a range of sowing times spread over several months. You should only sow during the earliest months if you can maintain suitable warmth for the germination of the seeds and if you can provide a light position for the seedlings afterward. The later months are more appropriate if you do not have a greenhouse and cannot provide ideal conditions.

Pricking out seedlings

As soon as seedlings produce their first true leaves (these tend to look quite different from the seed leaves), they can be pricked out into trays of compost. Handle each seedling very gently by one of the seed leaves, not by the stem. Ease the roots out using a dibber or the sharp end of a pencil and make a small hole in the compost to accommodate the root.

If the seedlings have become slightly leggy, plant them a little deeper than they were growing originally. Firm them in lightly and water with a fungicidal solution, if damping-off has been a problem.

Tiny seedlings, such as lobelia, are best pricked out in small clumps to prevent damage; they can remain in clumps when planted out in the garden, to give a better display.

Grow seedlings in warm, light conditions, but protect them from strong, direct sunlight. Apply shading to the greenhouse glass if necessary. Indoors, make sure the seed trays get as much light as possible and turn them daily to encourage the seedlings to produce even growth.

Sow seeds in March

Most hardy annuals produce stronger plants if they are sown in pots and trays under glass rather than directly in the soil. Use an unheated greenhouse or sheltered cold frame. Young plants can be used either to fill any gaps in the border or for growing in containers.

Good plants to grow in this way are alyssum; calendula such as ‘Fiesta Gitana’; star-of-the-veldt (Dimorphotheca); clary (Salvia viridis) and nasturtium, especially ‘Alaska’.

To avoid root disturbance at planting time, prick out the seedlings into small pots or cells in a modular tray.

The instructions on the seed packets for many hardy annuals recommend that you sow seeds in March, but in most areas, this means from late March unless you are sowing under cloches or another form of protection.

Do not rush to sow annuals. If the soil is too wet, too cold, or too dry, germination will probably be poor. Moreover cold, windy weather or the unexpected return of night frosts will kill vulnerable seedlings and check the growth of others. If you wait for a few weeks you will get better plants in the long run.

Heathers

Pruning summer-flowering heathers

Cut off the dead flower spikes which have protected the summer-flowering heathers throughout the winter. Pruning too early risks damage from the late frosts, too late delays flowering, and can cause the heathers not to flower at all. If you do not prune, the plants become straggly and unsightly and the life of the heather bed is shortened.

Use secateurs, scissors, or shears, whichever is most convenient, and cut off stems at the base of the flowers without cutting into old wood. As the plants become older, take less off the top. Also, check the varieties with colored foliage for any stems which have reverted to green. Cut these stems out completely otherwise the green foliage will take over and the plant will revert totally.

Prune young tree heathers by cutting off half of last year’s growth; this ensures a shapely plant in future years. Once they are three or four years old, confine pruning to shaping after flowering. Pruning in March causes a two or three-week delay in flowering, so prune the whole bed not just individual plants.

Checking heather layers

Check that the shoots you have layered are well-rooted by gently lifting the stem. If resistance is felt, cut these stems at ground level near the parent plant, but leave the layered stems undisturbed. They should be replanted next month.

Last summer’s cuttings

Using an ericaceous compost, plant the rooted cuttings deeply in pots, burying any bare stems, so that the lower foliage rests on the compost surface. Firm well to stop the cuttings rocking in the wind. Place the pots outside in a sheltered area.

Watering

Potted-up plants will dry out very quickly in dry weather, keep them moist and water daily if necessary. Rainwater is best, but if none is available, use tap water. Never use domestic softened water.

Carnations & pinks

Planting  in March

Sturdy container-grown pinks and border carnations can be planted out now in staggered rows, at intervals of about 25 cm (10 in), incorporating bone-meal into the soil.

Stopping and staking

Stop pinks that are running to flower without making bushy side growths by snapping off or cutting out top growth above the tenth joint – tops snap off cleanly in the early morning when the plants are crisp. This treatment may be used for all types of border pink, of any age if the plants look leggy. Border carnations, however, are bushy by nature and should not be stopped. If border carnations grow too tall and start falling over they should be discreetly staked.

Some border pinks produce flowers on the initial upright stem without making bushy plants. To encourage more side shoots, snap out the top of the stem after ten joints have developed.

Sideshoots will soon form once the growing tip has been removed, and this will mean more flowers to enjoy. Only stop pinks; border carnations should not be stopped.

Controlling pests

The chief pests of pinks and border carnations are aphids, thrips, caterpillars, and carnation flies. Slugs may also be a problem during warm, damp spells.

Rust, leaf spot, and other diseases

While gardening in March, check regularly for any signs of the diseases to which the dianthus family is vulnerable. Most modern hardy carnations and pinks are resistant to rust, though older varieties are often susceptible to this fungal disease. Rust usually starts near the base of the plant and this is recognizable by small yellow blisters which burst to release a reddish-brown powder. Poor air circulation helps to spread this type of fungal disease.

Leaf spot diseases show first on older leaves as brownish-purple patches and can be treated with a fungicide. While unattractive, these diseases are rarely fatal and plants otherwise thriving will usually overcome them. If they do not, take cuttings from healthy growth and start again, or replace them with fresh stock.

Some diseases are incurable, including stem-rot at ground level, which results from over-deep planting or poor drainage and wilts disease, characterized by yellowing of the top growth followed by the total collapse of the plant. Lift any affected plants, including the roots, and dispose of them. Avoid using the site for any dianthus species for two seasons.

Sow seeds in March

Continue pricking out seedlings of annual carnations under glass, and sowing seeds of all dianthus species and varieties.

Perpetual flowering
Healthy environment

Maintain a minimum temperature of 7°C(45°F) in the greenhouse. You will need to increase the ventilation in warm weather.

Keep a careful watch for pests and diseases, and act quickly if necessary. Destroy any plants infected with wilt or debilitating virus disease and maintain good greenhouse hygiene at all times. Damp down the floor and staging if the atmosphere becomes too hot and dry. This will discourage infestations of red spider mite.

Potting on and stopping

Continue to pot on new plants as their roots fill their containers and stop young rooted cuttings. Cut any blooms and disbud flower stems as necessary.

Buying new plants

When buying plants from a garden center or nursery, choose plants that show healthy top growth and are clearly labeled. Avoid plants with damaged or dying leaves, and those in moss-covered containers or with loose or dried-out compost.

Although most nurseries and garden centers sell the majority of their plants in containers all year round, spring and autumn are still the best time for planting. Soil temperatures and rainfall are generally more favorable at these times and plants have a better chance to establish themselves than in the cold winter or hot, dry summer months.

If, for some reason, you do buy plants in containers when it is not possible to put them straight into the ground, put the containers in a sheltered corner of the garden until the conditions improve.

Some nurseries stock field-grown perennials (that is plants grown in open ground rather than containers), which are best purchased when the weather is suitable for immediate replanting. If you cannot do this, heel the plants into trenches or place them in boxes of damp soil, first moistening the roots of any plant that has dried out.

Good Shops to try:

https://www.flowerseedstore.com/carnation-seeds.html

https://www.etsy.com/market/carnation_seeds

Container gardening

Removing insulation

In most parts of the country, the severest winter weather will have passed by mid-March and vulnerable pots and tender shrubs can be unwrapped from their insulation. You can also untie the anti-snow damage bindings on conifers and other shrubs. Do be guided by the weather; if it is still very cold and frosty then delay this for another week or two.

Planting in March

Try to finish planting in March before the new leaves of new deciduous trees and shrubs open out. Finish pruning and shaping deciduous shrubs that are normally pruned when dormant.

It should be easy to spot any dead wood now as buds on living shoots will have started to swell and expand. Don’t prune those shrubs that flower on wood produced the previous year – these should be pruned when they have finished flowering.

Bulbs and tubers

Buy summer-flowering bulbs before stocks run out for planting in April and May. Start begonia tubers into growth.

Replanting and top dressing

When a pot becomes full of roots, it is time to replant. Choose a container that is just one or two sizes larger, and cover the drainage hole with crocks, stone chippings, or similar. Put in a little fresh compost. Remove the plant from its existing pot and, if possible, tease out a few of the roots at the bottom.

Put it in a new pot with some fresh compost on top. Leave about 2.5 cm (1 in) of space at the top to allow for watering. Next, fill in down the sides with compost and firm this in. Water thoroughly to settle the compost in the pot.

Repotted plants will continue to grow larger, but when a shrub reaches a particular size and you do not want it to get any larger, top-dress instead of repotting it. Do this by removing about 2.5 cm (1 in) of compost and replacing it with fresh compost. Add a slow-release fertilizer to feed the plant through the rest of the season.

To rejuvenate an old pot-grown shrub, remove it from its pot and tease off all loose soil from the rootball. Trim the roots lightly and replant, working new compost well in to fill any gaps. Trim back shoots to compensate for the reduced root area.

Buying early for summer

Young plants in plugs, or net pots, come into garden centers very early on. If you have somewhere warm and light to keep them, such a s a kitchen windowsill, heated greenhouse, or conservatory, you can get a head start by growing them to a larger size so that they make an instant display when planted out in May or June.

However, the roots of these tiny plants are very prone to drying out, so plant them directly into hanging baskets, or pots – there is no need to remove the net pots first.

Bulbs, corms & tubers

While spring-flowering bulbs are at their best, take time to visit gardens noted for their spring displays.

Planting in March

Plant in pots for late spring flowering. Keep in a warm humid atmosphere and water sparingly until the buds appear.

Deadheading daffodils

Remove flower heads from daffodils after flowering, to conserve the strength of the bulbs. Do not tie or bundle the leaves in an attempt to make them look tidy but allow them to die back naturally.

Planting in March

The last of the pot-grown bulbs, such as daffodils, narcissi, hyacinths, crocuses, and some smaller irises, will finish flowering this month. Plant them out at once, removing intact both the bulbs and the fiber or compost in which they were grown, to encourage growth that will replenish the bulbs for future flowering.

These bulbs are unsuitable for forcing again, so plant them in clumps between shrubs or herbaceous plants, depending on the bulbs’ size. They will flower again in two years’ time and thereafter in subsequent springs. Tulips are less likely to succeed using this method, but may well flower again for a year or two.

Snowdrops and aconites

If snowdrops and winter aconites are crowded and need replanting, lift them before the leaves die down. Separate the bulbs or tubers and replant them at their original depth.

Summer-flowering bulbs and tubers

Plant ‘De Caen’ and ‘Saint Brigid’ anemones for flowering during the summer. Plant lilies in their permanent positions. Divide any large canna roots and pot those into 20 cm (8 in) pots using John Innes No. 3 potting compost. Plant begonia tubers into pots of soilless compost if you did not do this last month.

If you have a lot of summer-flowering bulbs or corms of one type, you can plant them at fortnightly intervals during the next month or two. This will extend the flowering period throughout the summer.

Planting out gladioli

Plant gladiolus corms in the second half of this month if the weather is warm and the soil frost-free and not waterlogged. Wait until April in cold areas.

In a mixed border, plant the corms 10-15 cm (4-6 in) apart in groups. To provide cut blooms for flower arrangements, plant them in rows 30-40 cm (12-16 in) apart. For exhibition purposes, plant the corms sprouted from earlier flowering in either single or double rows. Allow 45-60 cm (1 1/2-2 ft) between single rows. Space double rows 30 cm (1 ft) apart, with a 60-90 cm (2-3 ft) gap between each pair of rows.

Plant corms a good 5 cm (2 in) deep. If you do not plant deeply enough the flower spikes may well collapse. The base of each corm must rest firmly on the soil in the base of the hole or drill. Plant cormlets saved from last year 2.5 cm (1 in) deep in rows 10-15 cm (4-6 in) apart. They can be set so that they are almost touching one another.

Naturalized bulbs

Growing bulbs in the lawn or rough grass is a popular alternative to planting them in borders or containers. However, some bulbs are more suited to this than others. Choose early-flowering, robust varieties that do not grow too tall (unless they are to grow in long grass). Check bulb catalogs for types that are recommended for naturalizing.

Some gardeners feed naturalized bulbs, but it is difficult to feed bulbs in grass satisfactorily without creating vigorously growing grass which then competes with the bulbs. Usually, the bulbs are left to depend upon the organic matter which accumulates from mowing the grass to provide much of their nutrition.

It is mostly spring-flowering bulbs, such as the ‘De Caen’ anemones that are naturalized in a lawn because of the need to mow the grass in summer. However, some summer-flowering bulbs can be naturalized very successfully in areas of long grass such as an orchard or wildlife garden. These bulbs include many alliums, such as Allium moly, and lilies. The former are normally planted in the autumn, but if it comes to lilies, you can start planting in March.

Bulbs can also be naturalized in the front of a shrub border or in a woodland garden. Dwarf autumn-flowering cyclamen such as Cyclamen hederifolium are ideal for naturalizing beneath trees. Planting in March is a good idea.

When choosing a site for naturalized bulbs bear in mind that the object is to get the bulbs to multiply freely and t grow undisturbed over a period of years.

Chrysanthemums

Gardening in March - 3. Planting

Early flowering (garden)
Preparing the soil

While gardening in March, you should continue to dig on light, sandy soil, incorporating well-rooted manure or garden compost into the top 15 cm (6 in) of soil. Test the soil for alkalinity if this has not been done.

Starting off overwintered stools

Pot up chrysanthemums that have been covered, or bed them out in cold frames. Firm the soil in the base of the frame and cover it completely with a piece of plastic sheeting. Then spread an 8 cm (3 in) layer of compost on top, pack it down lightly, and plants the stools about 10 cm (4 in) apart. This method gives better results when the plants are lifted to put in their final positions outdoors as they are easier to move and the roots extend readily into the soil.

Late flowering (greenhouse)
Moving plants to a cold frame

In milder areas, move plants in small pots from the greenhouse to a cold frame as soon as possible to harden them off. Protect them from slugs and snails and cover frames with mats or sacking at night if the weather turns cold and frost threatens.

Propagating chrysanthemums

All chrysanthemums are best grown from cuttings; plants increased by division will be inferior.

The time you spend while gardening in March is also the perfect time for the propagation of chrysanthemums, although large exhibition varieties should have been propagated in January and February. Some of the early-flowering and very late-flowering varieties should be left until April or May. You can also take cuttings of mid-season and late varieties grown in the greenhouse now as these will provide stock plants for further cuttings for rooting in June or July.

Generally, the best cuttings come from shoots some way away from the old stem. During sunny weather shade the cuttings and spray them lightly with clean water twice a day, morning and early afternoon. At the beginning of the rooting period, the cuttings will appear limp. Eventually, they will look greener and show signs of growth; when this happens, but not before, water the compost again.

  1. Select shoots about 3-5 cm (1½-2 in) long, with evenly spaced leaves of good color. Ensure they are free from insects and obvious disease. Shoots chosen for cuttings must not be tough or wiry.
  2. Remove the lowest leaves, and trim off the stem below the lowest leaf joint. Root in a moist cuttings compost with one-third perlite or washed sharp sand added. Keep in a humid atmosphere at about 13°C (55°:F) until rooted.
Potting on

When the roots have formed all around the base of the stem and grown to about 2.5 cm (1 in) long, it is time to pot up the cuttings. Take care when doing this not to press the tender roots too firmly into the compost or they will be damaged.

Bury the roots without covering any part of the main stem, leaving the top 1 cm (½ in) of the pot unfilled. Water in well by filling the pot to the brim then letting it drain. A good soaking will keep the compost moist for several days. plastic pots, being non-porous, need less frequent watering.

Label each pot with the plant’s name and the dates of rooting and potting. Stand them on a free draining base where they will get plenty of light and air, but protect them from draughts. Maintain an average temperature of 7°C (45°F).

Pot on cuttings of large exhibition varieties rooted in January and early February as soon as the roots have become well established since their growth will suffer if they are left too long in small pots. It is always important to keep exhibition varieties of chrysanthemums growing steadily all the time.

Dahlias

Ground preparation

You should continue to prepare beds while gardening in March. Although planting time is not until the end of May or June fertilize the ground now with a slow-acting feed.

Taking cuttings

To obtain new plants of specific dahlia varieties, you will need to make cuttings or divide old tubers.

Take cuttings from new shoots on tubers. The cuttings will root more quickly in a cool greenhouse if the pots are placed in a large box covered by a pane of glass, or a transparent plastic bag, to conserve warmth and moisture. On hot days place brown paper or newspaper over the glass to shade the cuttings.

If you have no greenhouse, increase your stock by dividing clumps of tubers.

Potting up early cuttings

Check on the cuttings taken in February and, if they have rooted, pot them singly into a good potting compost in 8 cm (3 in) pots.

Sow seeds in March

If you do not require specific varieties, you can raise dahlias from seed. Near the end of the month sow home-saved and commercial seed of bedding, cactus, decorative, and pompon varieties in pans or trays filled with fresh seed compost. Scatter the seeds thinly and cover with a further 5 mm (¼ in) of compost. Place the containers in plastic bags or cover with glass, and stand them in a greenhouse or propagator heated to 18°C (65°F). Remove the covering as soon as the seeds germinate. Prick out the seedlings into trays when they are large enough to handle.

Inspecting tubers

Continue to check on any tubers remaining in storage.

Fuchsias

Tender and half-hardy

Pruning in March

Prune half-hardy fuchsias kept under glass as soon as the plants start producing little pink ‘eyes’ on the bare branches. A little heat, about 7°C (45°F) will encourage early growth.

Potting back

Pot back last year’s plants if not done last month. Some plants are late starters and only now will have made sufficient growth.

Potting on

Young plants grown from cuttings will need repotting regularly so that growth is not checked.

Always use fresh potting compost and clean pots. Any good quality compost is suitable, but John Innes No. 1 is particularly good for this purpose. Keep pot size increase to a minimum – too much compost unoccupied by roots can turn the soil sour.

When potting, check for signs of winter-laid vine weevil grubs which, left undisturbed, would devour entire root systems.

Autumn cuttings should now be ready to pot into 9 cm (3½: in) pots.

Taking cuttings

Take cuttings from new growth. Normally a cutting consists of a shoot with three or four pairs of leaves, but small tip cuttings, taking the tip of the shoot with one pair of leaves, also work successfully for fuchsias. Insert the potting compost in seed trays or shallow pots. Firm well, leaving no air pockets.

Water in the cuttings or mist them, and keep them in warm but not over-humid conditions with insufficient moisture to stop them from wilting. With heat, the cuttings will usually root in about 10 to 14 days; without heat, they may take up to four weeks.

  1. There are various ways to take fuchsia cuttings. One of the easiest is to cut off lengths of new shoots with three to four pairs of leaves.
  2. Trim the stem with a sharp knife. Pull off the lowest leaves that would otherwise be buried by the compost.
  3. Fill a pot with potting compost. Making a hole with a dibber or pencil, insert each cutting. Firm well to ensure there are no air pockets.
Stopping

Stop any plants which have made insufficient growth (usually once they have two pairs of leaves). This means pinching out the central growing tip of each shoot. This will encourage the plant to produce side-shoots and promotes bushy growth. You can use the tips you have removed for further cuttings.

Planting in March

Mid-March is an ideal time for planting up hanging baskets as long as they can be kept under cover until all fear of frost has passed.; otherwise, wait until next month. If you want the best results from all fuchsia baskets, fill each basket with the same variety rather than a mixture. A 38 cm (12 in) basket will look full with only three plants.

Feeding in March

Start feeding now, with a high-nitrogen feed. Follow the manufacturer’s instructions for a weak dilution: it is better to give frequent weak feeds than strong feeds less often.

Providing shade and humidity

Shade new growth on plants under glass from direct sun and spray with water almost daily, but allow time for the foliage to dry before the evening. If necessary, damp down the greenhouse floor to reduce temperatures and maintain humidity.

Hardy

Weed round fuchsias carefully, as they have a shallow root system that can be easily damaged. In milder areas, strong new growth will appear at the base and you can then cut them back. More often this will be next month.

Irises

Controlling diseases

Examine bearded irises, pulling off any dead leaves and cutting-out brown leaf tips and spots. Check the rhizomes and cut out any areas affected by a disease such as soft rot. Disinfect your knife after cutting each rhizome to avoid the infection spreading from plant to plant. Dust cut surfaces of rhizomes with a fungicide.

Dig out and destroy any bulbous irises showing symptoms of fungus disease or virus attack.

Weeding and feeding

Weed growth around bearded irises can be a particular nuisance because of these irises from a tight clump. Take special care when loosening the soil around the rhizomes to get at weeds as the rhizomes’ roots are very near the surface.

Feed with a general fertilizer and mulch Iris sibirica and water-loving irises such as Iris  ensata and the Japanese hybrids to conserve moisture.

Apply a top dressing of sulfate of potash to early-flowering bulbous irises after flowering and when their leaves have started to lengthen; this will benefit next year’s flowers.

Cold weather protection

In warmer areas dwarf bearded irises may begin flowering and need protection.

Lilies

Gardening in March - 3. Planting

Protecting young shoots

March is probably the month when you first see shoots beginning to break through the soil surface. Apply a light mulch of well-rotted compost, manure, or chipped bark on top of the clumps of established lilies. Use cloches or loose litter (straw, bracken, chipped bark, or compost) to protect the young shoots against frost damage at night.

Sow seeds in March

In warmer areas sow seeds outdoors in a cold frame, 2.5 cm (1 in) apart and 1 cm (½ in) deep, in boxes 15-20 cm (6-8 in) deep. In cold districts wait until the weather warms up in April before sowing.

Seed trays sown earlier can go into a cold frame if greenhouse space is restricted, but do not allow the compost to dry out.

Planting in March

March is an excellent month to plant lilies outside, especially stem-rooting types. Aim to complete all the main planting before the end of the month.

Check for basil rot before planting. Set each bulb two and a half times deeper than the bulb’s height. Lilies thrive in well-drained, deeply cultivated soil that contains plenty of humus. They do not like poor soil or fresh manure. It is best to prepare the beds in advance adding plenty of leafmoulds or well-rotted compost. Dig the beds to a depth of 45 cm (18 in).

If you garden on heavy clay or badly drained ground and want to grow lilies, it is best to prepare a raised bed by adding topsoil enriched with plenty of leafmoulds or well-rotted garden compost to 25-40 cm (10-16 in) above the surrounding soil.

Forced bulbs

Plant any lilies you have purchased especially for growing in pots. When forced lilies are about to open reduce the temperature to around 13°C (55°F) to prolong their flowering. Feeding should also stop at this stage.

Pelargoniums

Potting up

Pot up rooted cuttings or young seedlings into 8-9 cm (3-3½ in) pots in a good seed or potting compost. Position the plants where they will receive good light – never crowd them together so that the light does not reach the lower leaves. Keep them moist at the roots, but never waterlogged, and maintain a dry atmosphere. Pelargoniums do not like high humidity, and are inclined to rot in a moist atmosphere.

Pot up plants as soon as they look too large for the pot. Tap the plant out of its pot to see how the roots are developing; if they are filling the pot, then it is time to move. plants remaining in the same pot without access to fresh compost will need feeding as they soon exhaust the nutrients in their potting compost. It is important to feed as soon as possible if the leaves begin to look paler than normal or growth is stunted.

Feeding in March

Give young plants a balanced liquid feed but, as they mature, change to one which is higher in potash, such as a feed formulated for tomatoes. If plants receive too much nitrogen they will grow large leaves to the detriment of their flowers.

Shaping

Keep turning plants so that they do not grow ‘one-sided’. This is especially important for any plants on windowsills that receive light from only one direction. Pinch out the growing tip to encourage a bushy shape.

Stopping

If you are going to exhibit your plants they should now be receiving their last stopping. This is a matter of judgment, but leaving it too late could delay the flowering too long.

Cuttings

Continue to propagate pelargoniums while gardening in March, including scented-leaved varieties, from cuttings in a heated propagator.

Roses

Planting in March

Planting bare-root roses must be completed by the middle of the month, or by the end of the month in cold areas. As with any planting in whatever season, the site must be properly prepared beforehand and you should add at least one large forkful of well-rotted garden compost or manure per plant.

If you are replacing a plant damaged during winter, the soil in the immediate vicinity must be replaced for much the same reason that vegetable crops are rotated. The soil can suffer from ‘rose sickness’; when it becomes exhausted from supporting roses. Remove the soil to a depth of 45 cm (18 in) and replace it with fresh soil taken from a part of the garden where roses have not grown for five years.

All newly planted roses must be trodden in very firmly and, if the weather has been frosty, reform plants that were planted or transplanted during the autumn and winter.

Pruning in March

March is the traditional month for pruning most types of roses. In mild areas, late February is not too soon and you should have completed all pruning in March, even in the coldest regions.

In theory, all stems that produced flowers the previous season are now obsolete and must be removed. In practice, this is not possible as the bush must be allowed to build up a framework of branches. Whether the rose is a hybrid tea (large-flowered), floribunda (cluster-flowered), patio, miniature, or recurrent-flowering shrub, the procedure is the same.

First, identify the three categories of wood that constitute the roses. They are the old and decaying stumps, small twiggy growth, and the good, strong, healthy growth.

The old stumps should be removed in their entirety, although in practice this often difficult because they are inaccessible. Any dead or decaying wood must be eliminated as this is the source of many diseases. Long-armed pruners or a pruning saw are ideal for this purpose; never use good sharp secateurs on this type of wood as they are not strong enough and you will damage them.

Next, all very thin spindly wood must be cut out. This is the type of wood that does not have the potential to support new, strong growth to encourage new shoots. Then shorten the strong shoots by two-thirds to an outward-facing bud.

Established hybrid tea (large-flowered) and floribunda (cluster-flowered) roses benefit from strong shoots being cut back by about two-thirds. Cut out very old stumps, dead, diseased, and damaged wood, and any spindly shoots, completely.

Prune ordinary standard roses (not weeping standards) by cutting out very old or damaged wood, then reducing the rest of the shoots by about two-thirds, being careful to retain an even shape.

Only established repeat-flowering climbers (those that bloom from mid-summer to mid-autumn) should be pruned now. Cut out any dead or diseased wood, and shorten side shoots that flowered last year to about half.

Bush roses

These include hybrid tea (large-flowered) and floribunda (cluster-flowered) roses, as well as miniature and small patio types. A bush rose is one that is not trained into a special shape and does not have a sprawling or climbing habit.

Cut down newly planted roses to about 15 cm (6 in) and see that they are trodden in firmly. On established bushes, cut out old stumps and diseased wood and remove twiggy growth (miniatures, in particular, develop a tangle of thin branches in the center of the bush). Cut back strong shoots by two-thirds to an outward-facing bud.

Summer flowering shrub roses

Old garden roses which include gallicas, damask, albas, centifolias, and moss roses, are pruned in the same way as most shrubs, for rejuvenation rather than the size of bloom.

Newly planted shrubs will not require pruning in March. Apart from cutting out dead and damaged wood on established shrubs, the chief criterion is to cut back old flowering wood by a third to a half with an emphasis on giving a good shape to the plant. If a shrub is getting too leggy, reduce the number of stems by cutting down one or two to about 15 cm (6 in) encouraging new shoots to break from the base.

Climbers and ramblers

Only repeat-flowering climbers are pruned in the spring; climbers and ramblers which flower once only in the summer are cut back in autumn. Newly planted climbers and ramblers do not require any pruning in March. Check with an expert the type of rose you are dealing with if you are not sure.

Remove all damaged wood and non-productive stems on established repeat-flowering plants. Reduce the previous year’s flowering growth by half, taking out some side shoots completely. Cut all the old ties and rearrange the rose to give a good spread over the wall or fence. Tie in using soft string rather than plastic ties.

Ground cover roses

This type of rose must be allowed to grow naturally and cutting back will encourage inappropriate growth.

Standards

Prune back main stems of the top growth of newly planted roses to 15-20 cm (6-8 in), preferably to outward-pointed bud. On establishes standard forms of hybrid tea (large-flowered) and floribundas (cluster-flowered) roses remove old and damaged wood and reduce the main fabric of the plant by two-thirds, taking care to maintain a neat, even head.

Weeping standards are created by budding ramblers onto an upright stem, and so should be treated as other ramblers by lightly pruning back in the autumn.

After pruning in March

Check all stakes and ties. Do not leave prunings lying around. Dispose of them or shred them before composting. Spray all plants and the surrounding soil with a systemic fungicide and mulch the soil.

Sweet peas

Planting in March

As soon as soil and weather conditions permit, plant autumn sown seedlings that have overwintered in pots or trays. Spread the roses out well in the holes and plant them firmly. Discard all plants which have a brown collar on the white part of the stem above the seed.

If planted, these invariably collapse prematurely. Loosely tie the seedlings to stakes, or place small supporting twigs around each plant to prevent damage from wind rock.

Plant in pairs with 15 cm (6 in) between each pair in single rows wherever practicable. To support the growing plants, use 1.8 m (6 ft) bushy sticks or branches, bamboo canes, or wire netting.

Sweet peas planted in 30 cm (12 in) or 45 cm (18 in) circles at the back of the border look especially attractive. The old-fashioned varieties are particularly suitable for natural culture. Support dwarf sweet peas with tent-shaped lengths of wire placed over the rows.

This has a double value, as it also keeps the birds off when the plants are young. The ‘Snoopea’ and ‘Supersnoop’ types which have no tendrils will not need support. They can also be grown in containers and hanging baskets.

Protect the new plants immediately from birds and slugs and consider applying a mulch to conserve water.

Twiggy sticks make natural-looking support for sweet peas if you are growing them on a border. Use small sticks for dwarf varieties and taller ones for the larger upright kinds.

If you are growing sweet peas in rows to provide cut flowers then netting stretched between stout posts is a convenient way to support a number of plants. Alternatively, grow them up bamboo canes.

Planting for growth as cordons

To grow exhibition-quality blooms on the cordon system, set the plants out in double rows spaced at least 30 cm (12 in) apart with a pathway at least 1 m (3 ft) wide between each pair of rows. Allow 20 cm (8 in) between plants. Insert a 2.5 m (8 ft) cane alongside each plant and attach the canes to the support framework by typing them in or using cane clips to hold them steady.

Sow seeds in March

Soil and weather conditions permitting, sow seeds outdoors in their flowering positions. Make spring sowings under glass as early in the month a possible.

Vegetables

Gardening in March - 3. Planting

This is the month when many vegetables are sown. Prepare seedbeds if this has not been done already.

Apply fertilizers according to the fertility of your soil and the crops you intend to grow. If you add well-rotted organic matter, such as farmyard manure or spent mushroom compost, to the soil every year then you may not need to apply any additional fertilizer. Most garden soils contain plenty of nutrients, apart from nitrogen which is easily leached out of the soil. For the majority of leafy crops, you can use a straight nitrogen fertilizer to counteract this. For root and fruiting crops, it is better to use a balanced fertilizer.

Put down black plastic mulches to suppress weeds. This technique works well for widely spaced crops such as courgettes, marrows, cabbages, cauliflowers, and Brussel sprouts. Rake the soil into a slight mound and bury both edges of the plastic sheeting in slit trenches at either side of the bed. Use a knife to cut holes through the sheet and plant seedlings with a trowel or dibber as usual.

While gardening in March, take some effort to protect plants from slugs and snails if the weather is mild and damp.

Consider starting seeds off in 8 cm (3 in) pots in a greenhouse rather than sowing direct into open ground. If you do not have a greenhouse, use can use a cold frame for pots of the hardier vegetables such as lettuces. Tender crops, such as French beans, tomatoes, and sweetcorn, can be started off on a windowsill indoors.

Sowing in pots means you can easily protect young plants from bad weather and soil pests. Most pot-grown crops can be planted out or potted on within four weeks of sowing. To harden them off put the pots outside during the day for a couple of weeks, bringing them in at night. Then plant out the seedlings in their final growing position in a prepared bed.

The advantages of this early start are twofold; first, there will be no need to thin the crop, and secondly crops are ready up to two weeks earlier than if directly sown into seedbeds.

Beans

Sow broad beans in pots if they have not been sown earlier. Plant out those sown last month. Broad beans can be sown in double rows with plants 20 cm (8 in) apart from each way, in single rows 45 cm (18 in) apart, or in blocks with plants 20-30 cm (8-12 in) apart.

Brassicas

Give overwintered brassicas a high-nitrogen feed at the start of the growing season, by adding a suitable nitrogenous top dressing.

Summer cabbages, cauliflowers, and Brussel sprouts are best started off in pots under glass. If you grow a few like this in succession you avoid a glut at harvest time. Sow two or three seeds in each 8 cm (3 in) pot and if more than one grows, pull out all but the strongest. The alternative is to sow in rows in a seedbed and transplant the young plants to their final positions in late May or early June. Sow 2.5 cm (1 in) deep in rows 15 cm (6 in) apart.

Make the first sowing of an early calabrese variety. Sow a couple of seeds per pot, germinate at 15°C (60°F), then keep well watered and frost-free. They should be ready for planting out under cloches in six to eight weeks from sowing.

Cut the first spears of early sprouting broccoli and the heads of winter cauliflower, planted the previous summer.

Carrots and parsnips

In mild areas, sow short rows of an early carrot such as ‘Early Nantes’ for a succession of baby carrots in the summer. Later in the month start sowing maincrop carrot varieties such as ‘Autumn King’ in rows 15 cm (6 in) apart. Thin the seedlings later to one about every 5 cm (2 in).

Parsnips can be sown now in mild areas, but in most places, they are better sown in April or May.

Celery

Celery is one of the hardest vegetables to grow well; self-blanching types are easier than traditional trench celery. To germinate, celery seed must have light and a minimum temperature of 15°C (60°F). Sow seeds thinly on a tray of compost in late March. Do not cover them and keep the compost moist. It may take a month for the seeds to germinate. If you cannot provide these conditions, buy-in young plants.

Onions and leeks

Give overwintered (Japanese) onions a high-nitrogen feed at the start of the growing season.

Onions can be grown from seed or from sets (small onions). Sets are the easiest option but there is a greater choice of varieties from seed. Onions raised from seed are also less likely to bolt and generally store better.

Sow seeds in pots in a cool greenhouse and harden them off before planting them out in April. Seeds can also be planted outside, with or without a cloche. Sow 2 cm (¾ in) deep, with 30 cm (12 in) between the rows. Thin the seedlings to 3 cm (1½ in) apart.

Plant onion sets from early March onwards. Push them gently into the soil, spacing them 5 cm (2 in) apart in rows 25 cm (10 in) apart. Plant shallots 15-20 cm (6-8 in) apart, with 30 cm (12 in) between the rows. Leave just the tips of the onions and shallots exposed and cover them with fleece or netting to prevent birds from pulling them out.

Sow leek seeds under glass, 2.5 cm (1 in) apart. Prick out the seedlings to about 3 cm (1 1/2 in) each way when they are large enough to handle. Start to harden off the seedlings up to a month before plating outside. You can also sow direct outside but cloches or fleece may be needed in cold areas. Sow the seeds 2 cm (¾ in) deep, with 15 cm (6 in) between the rows. The thin out to 3 cm (1½ in).

Other roots and swollen stems

In mild areas, start to sow beetroots little and often for a succession of tender baby beets throughout the summer. Sow beetroot about 2 cm (¼ in) deep; each seed capsule will usually produce up to four seedlings. Thin to about 5 cm (2 in) between plants and allow 15 cm (6 in) between rows.

Sow celeriac seeds if not done last month. Prick out celeriac seedlings sown last month.

Kohlrabi is a member of the brassica family that produces swollen stems instead of roots. They are grown and used in the same way as turnips. Sow a succession, leaving 30 cm (12 in) between rows and 25 cm (10 in) between plants.

Peas

Make the first successional sowing of peas if not done already. An alternative is to sow an early variety and the main crop like ‘Hurst Green Shaft’ at the same time to spread the harvest.

Mangetout peas and snap peas are worth trying. As you eat the pods whole, this saves time and preparation when cooking. Both are grown like ordinary garden peas. Taller varieties of peas need support in the form of canes and string, netting or twiggy brushwood, the traditional pea sticks.

Potatoes

Chit maincrop potatoes.

Plant sprouted tubers of early varieties 10-15 cm (4-6 in) deep. Space them 40 cm (16 in) apart in rows 45 cm (18 in) apart. Draw the soil around them from either side to form a flat-topped ridge up to 30 cm (12 in) high. Do this in several stages as the plants grow.

An alternative is to plant the tubers in a trench and then cover them with a thick mulch of well-rotted organic matter or old straw. Some gardeners add grass clippings to the trench when planting in March to keep the tubers clean. Protect the foliage if frost threatens with a double layer of horticultural fleece. Soak the soil every week during dry spells.

Salad crops

In mild areas, start to make sowings of salad crops such as lettuces, radishes, and spring onions. To prevent a glut, sow them at intervals so that the harvest is staggered – crops such as these are best harvested little and often.

Sow lettuces 2 cm (¾ in) deep; if the soil is dry, water the bottom of the seed drill before sowing. Mature lettuce needs a space of up to 30 cm (12 in) in diameter.

If sowing in rows, allow the following space between rows and plants; 2o cm (8 in) for small lettuces such as ‘Little Gem’; 30 cm (12 in) for butterhead, cos, and salad bowl types; and 40 cm (16 in) for crispheads. In cold areas, start lettuces off in pots under glass.

Spinach and spinach beet

In mild areas, make the first sowings of spinach and spinach for a succession of crops. Avoid a glut by sowing small amounts at regular intervals so that the harvest is staggered throughout the summer.

Sow spinach and spinach beet about 2 cm (¾ in) deep, in rows 30 cm (12 in) apart, thin the young seedlings to 10-15 cm (4-6 in). In cold areas start spinach and spinach beet off in pots under glass.

Tomatoes, peppers, and aubergines

In most parts of the country, greenhouse tomatoes are more reliable than outdoor varieties. In milder areas cordon types can be grown successfully outdoors, but bush varieties are earlier and easier to grow in most places. ‘Tumbler’ is good for container growing. Sow outdoor varieties in a heated propagator at 15-20°C (60-70°F).

Seedlings should appear in seven to ten days. When they are large enough to handle, prick out individually into 8 cm (3 in) pots of multi-purpose compost and grow on in the greenhouse. If you do not have a propagator use a warm windowsill or buy plants from a garden center in late April or May.

Peppers require similar conditions to tomatoes. Grow them in the greenhouse or, in mild areas, under a cloche when young. Sow two seeds to each pot and keep in a propagator at 18-20°C (65-70°F) until germination, then remove the weakest seedling.

Aubergines are worth trying in milder areas. Growing under cloches will improve the chance of fruit ripening. Sow seed 5 mm (¼ in) deep in pots in a propagator set to 18-20°C (65-70°F).

Turnips and swedes

Sow turnips 2.5 cm (1 in) deep; if you want to harvest baby turnips make the rows 25 cm (10 in) apart with 15 cm (6 in) between plants. Sow turnips for storage with 30 cm (12 in) between rows and 25 cm (10 in) between plants.

Sow swedes 2.5 cm (1 in) deep, in rows 40 cm (16 in) apart with 25 cm (10 in) between plants.

Perennial vegetables
Asparagus

Prepare an asparagus bed by digging the soil over and removing every bit of perennial weed you can find. Add plenty of organic matter, such as spent mushroom compost, before planting. Allow 1 m (3 ft) between each row and 45 cm (18 in) between plants when planning the bed.

Rhubarb

Blanched shoots should be ready outdoors in the first half of March.

Gardening in March – Other Parts

Gardening in March – 1. Early Spring
Gardening in March – 1. Early Spring
Gardening in March brings fair-weather gardeners out of hibernation. Mid-March is usually the start of the spring season, providing opportunities for more varied gardening work with the increasing number of days of sunshine.
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Gardening in March – 2. Garden Work
Gardening in March – 2. Garden Work
Gardening in March has a great amount of garden work to be done. It is an extremely busy month in the garden, so if we do some things now we'll be able to get a major head start on the upcoming garden work.
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