Garden tasks for April: get ready for summer

This monthly guide is geared to London gardens and their unique conditions. Compiled by the RHS Wisley Plant Centre team
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It is a good idea to dead-head daffdils as soon as the flowers fade this month, sos that they will look fabulous next year
Don’t worry too much if your garden doesn’t seem to be flourishing as you have been hoping - this is all down to the cold of the last few months and it will pick up quickly as the weather warms up.

Must do in your garden this month

* Dead-head daffodils as soon as the flowers fade and leave foliage for a minimum of six weeks or until it yellows. During this time the daffodils carry all the nutrients down to the bulb and they will be needed for fabulous flowers next year.

* Before your evergreen hedges like yew and holly have a chance to get growing (and assuming the frosts have passed), grab this last opportunity to prune them to the desired height.

* It is time to complete your rose pruning now. Cut back to healthy strong shoots and then give them a good feed by lightly raking a rose fertiliser into the soil. Tie in the new growth on your climbing and rambling roses.

* Your shrubs will be hungry too. Feed with a general fertiliser like Vitax Q4 unless you have lime-hating plants (Rhododendron, Pieris, Enkianthus, most heathers and the like) in which case use an ericaceous feed.

* Yes, it’s boring, but keep those weeds under control before they take off. Pull up the root wherever possible. Actually this can be quite therapeutic and the end result makes it well worthwhile.

* Another job that you will regret if you don't do - put in stakes for fast growing perennials like Delphinium and Achillea. Pea-sticks and a variety of metal supports (or sticks and string) are available in the plant centres. They look unsightly at first but the plants will soon grow through and over them. Then they won’t fall over in the summer when it’s nigh impossible to put supports in place without breaking flowering stems. So do it now.

* If you have the lovely forsythia with its yellow flowers on naked stems, then prune it back to size when it has finished flowering. The subsequent growth will house next year’s flowers.

* Now is the time to start increasing the amount of water you give to houseplants. If you placed them in a sunny spot for the winter, then move back out of direct sunlight now.

* If you have evergreen ornamental grasses (try Festuca, Carex, Juncus or Luzula for example, there are lots) now is the time to cut back any old, tired foliage.

* If you’re lawn isn’t as you would like, apply a spring lawn fertiliser to encourage good, strong growth. If moss is a problem choose a combined fertiliser and moss killer. After a couple of weeks lightly rake the lawn with a spring-tine rake to remove dead moss and old plant debris.

A Magnolia x loebneri 'Leonard Messel' is a hugely popular addition to any garden, with its' beautiful star-shaped flowers

Nice to do in your garden this month

* Plant a Magnolia. Magnolia ‘Susan’ makes a small tree (deep pink, cup-shaped flowers) growing to about 12 foot. Or buy as a shrub - Magnolia x loebneri ‘Leonard Messel’ is hugely popular with white, star-shaped flowers. Dig in plenty of organic matter when planting and water regularly while the roots get established.

* Plant up a hanging basket and hang it in a frost-free greenhouse to grow on until the danger of frost has passed.

* Plant hybrid lily bulbs in containers for a spectacular summer display. Plant at two and a half times their height, spaced abut twice their width apart. Finish the surface of the compost with some grit or gravel and label. Place the pot in a sheltered spot.

* By now you should have some idea of which perennials survived the winter and what needs to be replaced this year. Have fun choosing new varieties in the plant centre. This is also a good time to move plants that may not have been well placed last season, for example hostas and ferns which may have been exposed to too much sun.

* Sweet peas can be sown outside this month. Plant out autumn-sown sweet peas that have been raised in pots (available in the plant centres ). Prepare a wigwam support for them to climb and use a light twine to tie the plants in. Await the scented blooms.

Start a herb garden this month and get the kids involved in the planting
* Start a herb garden near the back door with young mint, rosemary and tarragon plants. Sow seeds of hardy herbs like parsley and chives in nearby patches. Get the kids involved in the planting and the subsequent cutting for the cooking pan or plate.

* If your child(ren) prefer flowers then sow hardy annuals like pansies and nasturtiums which are very dependable and offer plentiful flowers.

* A birdbath can be a vital source of drinking water for birds. If you’re limited for space there are models available to attach to windows, walls and sills. Be sure to keep it topped up. Do change the water regularly and scrub the bath out with a mild detergent (available from bird food suppliers) to help prevent disease.

* Prepare for the Halloween pumpkin party. Start the pumpkins off in a heated greenhouse. Sow good quality seed in trays of good quality seed compost or you can sow singly in 7.5cm pots. If your garden is very sheltered, you can delay sowing until late spring and sow seed in open ground protected by glass. When they’ve grown into small plants distribute among your children’s friends and see who’s grows the largest by October 31st. ‘Mars’ and ‘Hundredweight’ are both easy varieties.

All images provided courtesy of the Royal Horticultural Society. Visit the online print shop at

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