Trees, Shrubs and Roses
Watch roses for a build-up of damaging numbers of greenflies - use derris or soap-based spray if necessary, and continue to spray against blackspot disease. Check the ties on all staked trees to ensure they are not too tight before new season expansion. Recently planted trees, shrubs and hedges need to be checked for water shortage and will need to be watered during dry spells that last for more than five days. Clip hedges that were not clipped earlier and those that have made early growth.
It is too early to plant out bedding plants, in all but the mildest gardens close to the south coast. Tidy up flower beds now before the weeds go too far; the ground is still soft and it much easier than it will be in a couple of weeks time. If you are raising your own bedding plants, these should be pricked out into trays or pots in good time and grown on strongly by adequate watering and liquid feeding. If they are developing too fast, simply stop feeding and ease off watering a little. Gladiolus and dahlias can be planted directly outdoors. Sow hardy annual flowers seeds to flower later in summer, especially nasturtiums.
Weekly mowing will be necessary from now until the end of June and perhaps after that if the weather is wet. Regular mowing keeps the grass down and encourages a good thickness of grass to develop. Lawns that are growing poorly will tend to be dull in colour or yellow and need feeding now with lawn fertilizer or high-nitrogen fertilizer. Keep lawn edges trimmed.
Fruit, Vegetables and Herbs
Apple and pear trees will need to be sprayed against scab diseases if there was scab damage in previous year. If not already done, apply some potash to fruit trees or a fruit fertilizer to improve growth and yield, but not rich compost or manure when tends to promote soft growth and diseases.Check for greenflies on fruit trees and bushes but do not spray when the blossoms are open in case of damaging pollinating bees and other insects. All kinds of vegetables can be sown, especially carrots, cabbage, peas, onion sets, potatoes and cauliflower. It is somewhat late for seed onions, but sets can be planted.Parsnips can be sown to give smallish roots. A first sowing of french beans can be made. Sow herb seeds too.
Greenhouse and House Plants
Plant out greenhouse tomatoes in the greenhouse soil or in pots, or growbags. All greenhouse plants should be well watered and liquid fed to grow them on strongly and take advantage of improving weather conditions. Sweet corn should be sown by now but can be put in right away, if not. Courgette seeds and runner beans can be sown for planting out at the end of May. Watch for greenflies and red spider mites, especially on peach trees.Summer bedding seeds sown this late will flower late in the summer and it might be better to wait and buy plants.