Garden Diary: April
Bulbs and flowers
Continue to lift and divide herbaceous plants. Finish dead-heading and cutting back. Leave penstemons until the end of the month, to protect the new shoots from late frosts.
Protect delphiniums and other perennials from slugs and snails. Plants are at greatest risk when the young shoots first emerge.
Deal promptly with any perennials weeds that are starting into growth.
Start planting perennials into the borders.
Place supports for oriental poppies, peonies, delphiniums and other tall plants.
Dead-head and feed daffodils and other spring bulbs, but don’t cut down or tie up the foliage for six weeks.
Buy summer flowering bulbs and tubers now, when the biggest range is available. Try planting lilies in pots so that you can drop them into gaps in the summer border.
Bring dahlia and canna tubers out of storage, dividing as necessary. Move to a bright, sheltered spot and water, to start them into growth.
Greenhouse and containers
Sow seeds of tender crops, like tomatoes, cucumber and aubergine, in propagators or on a warm window-sill.
If your greenhouse is heated, buy bedding and seasonal plants for containers now and grow them on. Remember to open vents and doors on warm days.
Start feeding houseplants and pot on any that are pot bound.
Trees and shrubs
Loosen off any tree ties that have become too tight.
Move evergreen specimens and plant evergreen hedges. Keep well watered until established.
Early in the month, prune leycesteria (Himalayn Honeysuckle) and buddleja (Butterfly Bush).
Pinch out hardy fuschias.
Prune forsythia and flowering currants (ribes) as soon as the flowers fade.
Trim rosemary and winter flowering heathers, to prevent them getting leggy.
Tie in clematis before they get out of hand – take care not to break the young fragile stems.
Start spraying susceptible roses with fungicide.
Feed roses, fruit trees and soft fruit bushes with a high potash feed. Make sure that the area around the base of the plants is clear of weeds and grass.
Give azaleas an ericaceous feed and mulch them (and rhododendrons) with ericaceous compost.
Spring frosts can cause damage after an early, warm spell. All young plants are at risk, as is any new growth on especially vulnerable, established plants such as pieris and hydrangea.
Prepare vegetable beds and cover with black plastic until ready to plant.
Sow seeds of hardy crops directly into the ground now.
Start succession sowing of salad leaves in the ground or containers.
Plant potatoes, onions and aparagus.
Start mowing, keeping the blade high for the first few cuts. Re-turf bare patches and apply a high nitrogen feed.
If weeds and moss are a problem, apply specialist treatments now.
Birds are nest building now. Consider giving them some help by raking up some moss and leaving it in a handy pile. Keep feeders topped up to fatten the adults up for the breeding season.