Trees, Shrubs and Roses
Check newly planted trees and shrubs, which are breaking bud and trying to leaf out, to ensure they are not short of water and water heavily to reach the roots. Spring-flowering shrubs, such as forsythia and flowering currant should be pruned as they go out of flower, if it is necessary to shape them or they are out-growing their space. Roses will need regular spraying against blackspot disease to protect the new leaves. It is now too late to move any shrub or young tree within the garden. Only container-grown trees or shrubs should be planted now.
Remove weeds in borders before they make much new growth, and tidy flower beds and borders that have not been already done. Watch for slug and snail damage to emerging shoots of perennial flowers, even below soil surface, during these weeks. Plant perennnials from pots and water well. Bedding plants raised from seeds should be pricked out and grown on strongly, spacing the plants well to give them room to grow. Tubers of begonias and dahlias, and corms of gladiolus can be planted out where they are to flower in the coming weeks. Sow seeds of cosmos, chleome and lavatera for showy summer displays in borders.
In spring lawns can be slow to begin growth if soil temperatures remain low, but grass can also be slow to start because of shortage of nutrients, especially nitrogen. Apply some lawn fertilizer, or high-nitrogen fertilizer.Trim lawn edges where they meet paths and borders.It is a good time to sow a new lawn or to over-seed an old one that is a bit thin. Scarify with a power-scarifier, which can be hired, then sow seed and feed at the same time. A poor lawn can be rejuvenated in a matter of weeks. Do not apply fertilzier to wildflower lawn areas.
Fruit, Vegetables and Herbs
Continue sowing vegetables, especially maincrop vegetables such as carrots, broccoli, cabbage, broad beans, peas, parsnips, beetroot and white turnips. Sow herbs seeds in warm weather. Sow cabbage and cauliflower soon for autumn and winter cropping. Sweet corn and runner beans can still be sown in the greenhouse for planting out later. Spray apple and pear trees for apple or pear scab disease and check for greenfly.
Greenhouse and House Plants
Houseplants can be re-potted now, if they are pot-bound and tend to topple over. Over-grown house plants can be cut back now and well watered and fed until they show signs of new growth. Feed all greenhouse plants strongly and water well to get the best benefit of the season with a good start. Spray a grapevine for mildew with rose sprays if it had the disease last year. Plant out greenhouse tomato plants, also melons and cucumbers if plants have been raised, or purchased.