Gardeners Diary - April Gardening

Any protection left on tender plants should be removed and those plants lifted and divided if needed.

Apply a mulch to prevent weeds. Empty spaces in your border can be filled with gladioli.

Cuttings of Michaelmas daisy are now ready for planting.

Thin out new shoots to encourage flowering on established plants and stake any needing support.

Finish preparing soil in beds and sow in drifts for the best display. Only sow if the soil is sufficiently dry. Start with annuals which take longer to germinate such as: Adonis, Clarkia, Lavatera (mallow) and Papaver (poppy).

Support Canterbury bells. Other biennials should be flowering and do not need much attention.

Sow Matthiola incana (week stock ten) seeds. Continue hardening off plants that have been pricked off.

Complete pruning not finished in March. Neglected and damaged shrubs can be revitalized now. Cut back drastically, leaving new shoots at the base, on plants such as Philadelphus and Syringa.

Plant evergreens.

Check ties and loosen or tighten as required. Give winter damaged plants time to recover then prune back to healthy wood.

Plant new specimens in a deep hole with well rotted manure added and angle towards the fence or wall.

It is now too late for planting bare rooted plants but container plants can be planted all year round.

An unusual effect can be produced by "coppicing" or "stooling". Cut back trees almost to the ground and the new fresh shoots grow carrying larger leaves. This works particularly well on Eucalyptus trees.

Plant evergreen and deciduous hedges this month. Spray newly planted hedges with water during dry weather.

Apply a mulch around newly planted hedges.

Prune established hedges when buds show signs of opening.

Trim any remaining winter flowering heathers and cut down to within 15cm (6 inches) any tree heathers that are becoming untidy.

Remove weeds and add a dressing of fertilizer.

Planting can continue until the middle of the month.

Plant summer flowering bulbs, such as Allium, when the risk of frost is over. In heavy soil, plant in a sandy mixture to encourage root growth.

Continue planting gladiolus corms.

This is the busiest time of year with regard to alpines as many plants are in flower and the new growth on others is progressing. Alpines need a lot of watering at this stage. Potting up and replanting continues.

Aphids and whitefly can be a problem at this time of year and need careful control using pesticides.

Cuttings can be made of Dionysia and Androsace.

Planting can continue in rock gardens until midsummer, although the earlier this is done the better.

Renew slug pellets as needed.

Increase the frequency of mowing. Try to keep the blade set above 5mm (3/16 inch) to reduce build up of moss and creeping weeds.

Feeding can be done now in the colder areas if it was not done last month.

Apply selective weed killer as fertilizer can result in vigorous growth of weeds and remove coarse grasses by hand.