Gardening Tasks for March

Herbaceous Perennials

Planting: Keep off the soil if it is sufficiently wet to stick to your boots. Compacting wet soils can damage their structure, especially heavy soils such as clay. On lighter soils, a good compromise may be to work from boards, which spread the load over a greater area.

In warmer areas aim to finish planting herbaceous perennials by the end of the month. In colder areas, they can be left for another two or three weeks. The holes should be large enough to allow the roots to spread fully. Fill in carefully and firm well.

In sunny, windy weather, young plants are prone to wilting, so look out for this. If the plants need additional water use a fine spray or watering can rose.

Tender Plants: In warmer areas, remove the covering from tender plants if they show signs of fresh growth. Left on, the covers may harm the young shoots. In colder areas, wait a few more weeks until you are sure the worst of the weather has passed.

Sowing seeds: Perennial seeds that may be sown now include Delphinium, Aquilega, Papaver orientale, Eryngium, Armeria, Gypsophilia, Limonium. If sown in gentle heat, they will germinate in two or three weeks and make good plants by the autumn.

Cuttings: delphiniums brought into the greenhouse in January should now have made sufficient growth for cuttings to be taken. Delphinium cuttings can be taken using the following method: Use a jam jar that is not too deep, as it is better to keep most of the foliage out of the container. Place a thin layer of sharp sand on the bottom with about 2.5 cm of water.

Take 10-15 cm long cuttings from low down on the crown so that the base is solid. Prepare them by trimming off the lower leaves and stand a number of them in the container.

All that is needed is to keep the water topped up to 2.5 cm mark. Roots should have appeared within about three or four weeks and the cuttings can then be potted up. They need handling with care, however, as roots produced in water tend to be brittle and do not become readily established.

Hardy Annuals

Provided that the soil is not at all sticky, towards the end of the month, spread a dressing of bonemeal on beds prepared in the autumn. Then break up the surface with a fork.

Sweet Peas

Plant out October-sown seedlings, soil and weather permitting.

Biennials

If you have been unable to cultivate the soil among your biennials, do so now. Sow pansy seeds.

Half-hardy Annuals

Sow seeds of Ageratum, Dahlia, Tagetes and Zinnia.

Seedlings pricked out earlier in the year can be moved to a cold frame, weather permitting, at the end of the month. Keep the frame closed unless the weather is very warm. If there is any fear of frost, cover it with sacking or some suitable alternative at night.

Seeds sown last month should now be large enough to prick out.

Roses

Early March is a good time for pruning if you live in warmer areas. In colder areas it is best to leave it until the end of the month. avoid pruning during frosty weather.

Generally, strong-growing varieties need the least severe pruning. the weaker types need cutting back fairly hard to encourage growth. Always cut back to a dormant, outward-facing bud, ansd use sharp secateurs. A clean cut is essential.

You may sometimes find that an apparently healthy shoot is brown inside when you make a pruning cut. This is particularly common after a severe winter. It is essential to cut back to white, healthy wood, even if this means cutting down to ground level. If possible, burn all rose prunings immediately.

Shrubs and Climbers

March sees the start of the annual pruning cycle, in this case concentrating on shrubs that will flower later this year on the growths they make during the next few months.

Shrubs needing regular pruning fall into two distinct groups – those that flower on growths (wood) formed the previous season (group 1) and others that flower on the current season’s growth (group 2).

Group 1. Flowering on shoots that developed and ripened the previous year, the majority bloom during the earlier part of the season. Clearly, pruning once the shoots have started to grow would mean loss of potential flowers. For this reason, Group 1 shrubs are pruned as soon as they finish flowering, removing as much of the flowered wood as possible and cutting close to suitable new growths lower down the stem. The new shoots will then have the rest of the season to grow and ripen. Plants in this category include Forsythia, Philadelphus, Weigela, Spirea.

Group 2 In this case, flowers are carried on shoots that have formed during the same growing season. If such shrubs were left unpruned, the new shoots would emerge towards the ends of last year’s wood, resulting in an open, lanky plant with poorer flowers. Pruning consists of removing last year’s shoots almost to their point of origin, cutting back to the first good bud, or pair of buds, at the base.This will result in healthy new shoots that will flower later in the year. Late March or early April is the ideal time for doing this, to ensure the new shoots avoid the worst of the frosts. Examples og shrubs in this group are Buddleia davidii and Perovskia.

Trees

Buying trees for planting: The nearer the end of month, the more urgent the need to complete planting of bare-rooted trees. Make sure, however, that the ground is moist enough, if necessary, watering after planting. Balled trees can be delayed for a few weeks longer, especially if the roots are wrapped in hessian. Container-grown trees may be planted all year-round, subject to weather and soil conditions.

Bulbs and Corms

This is the best time to move snowdrops (Galanthus species). They are one of the exceptions to the rule that bulbs should not be moved while growing. Although they may look rather untidy when first moved, they soon recover.

Plant gladiolus corms as soon as the soil is in a suitable condition.

See also Veg Gardening in March

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