Trees, Shrubs and Roses
Spring shrubs, such as forsythia, kerria and spring spirea, should be pruned as they go out of flower, if necessary, but if there is plenty of space, let them grow. Roses need regular spraying against blackspot disease which destroys the leaves. This is a key time to prevent the infection of the new foliage. Check that young trees and shrubs planted last autumn and in recent months are beginning to show signs of growth and make sure they do not dry out in a dry spell, or have been rocked by winds. If this is the case, firm them well and use a stake it necessary. Check the ties on wall shrubs to ensure they are not too tight as the shoots expand during the growing season.
As the weather warms up, slugs and snails become very active on warm damp nights and they can cause severe damage as new foliage comes through the soil and especially on small new plants. Sow seeds of cosmos, sweet peas and lavatera for showy summer displays in borders. Tubers of begonias and dahlias can be potted up, or planted out towards the end of the month, and corms of gladiolus can be planted out where they are to flower. If you sowed seeds of bedding plants, they will need to be pricked out and grown on strongly by regular watering and feeding, making sure to space them adequately.
In general, lawns benefit from some lawn fertilizer or a high-nitrogen fertilizer.Sow a new lawn or to over-seed a patchy old one. Moss can stil be controlled with sulphate of iron and make sure to feed the grass afterwards to provide a boost.Trim lawn edges where they meet paths or borders to give a neat result.Do not use any fertilizer or lawn weedkiller on a wild flower lawn.
Fruit, Vegetables and Herbs
Sow vegetables as the opportunity presents itself, especially maincrop vegetables, such as carrots and peas, and repeat sowings of small amounts of salads. Sow french beans as soon as the soil warms up. Stay on schedule for sowing cabbage and cauliflower for autumn and winter in the next few weeks. Sweet corn and runner beans can be sown in the greenhouse for planting out later. Spray apple trees for apple scab disease and check for greenflies at the same time. Herb seeds can be sown now too. Control weeds between vegetables by hoeing on a dry breezy when they are still seedlings. Remove weed seedlings close to vegetables by hand - it takes less time when the weeds are small.
Greenhouse and House Plants
If not already done, greenhouse tomato plants, raised or purchased, can be planted in the greenhouse soil, also cucumbers, chillies, aubergines, sweet peppers and melons.Over-grown house plants can be cut back now and well watered and fed until they show signs of new growth. Houseplants can also be re-potted now, if they are pot-bound and topple over at a touch. Move plants into bigger pots as they need it, such as begonias, dahlias and bedding plants. Feed house plants and all kinds of greenhouse plants to make rapid growth early in the season. Spray a grapevine for mildew if it had the disease last year. Remove excess shoots of a grapevine every couple of weeks to keep it under control and tie in new shoots that are needed for extension growth.