Essential tasks for April
Keep your garden looking its best with our guide to essential tasks that need doing in April.
In the Flower garden
Prune shrubs: Many shrubs will benefit from a trim this month to keep them tidy and encourage new growth. Shorten the shoots of cape fuchsia, cutting back to strong sideshoots, shaping the plant and relieving congestion. Trim over lanky winter-flowering jasmine, Jasminum nudiflorum plants and tie in long shoots to their supports to tidy the display.
Hard pruning: Hard prune tall old stems on Buddleja davidii, Leycesteria formosa and other fast-growing shrubs that flower on new wood. Many dogwoods and willows, grown as clumps and valued for their colourful winter stems, should also be cut back hard now, right down to a stubby base, about 30cm (12in) from the ground. Other shrubs that respond well to hard pruning include the golden-leaved elder, smoke bush and purple hazel, which will then produce fresh young growth and often brighter and larger leaves.
Keep spring pots looking good: A little attention to spring-flowering pots will ensure they look their best right through until May. Pick off dead flower-heads from primulas and winter-flowering pansies to encourage plants to develop further flowers. Also pick off the faded heads from spring bulbs, such as daffodils, but leave their foliage intact. Compost in pots can also dry out, so check with a finger to see how moist it is, and water well if it has dried out.
Heathers: Clip old flowers off winter-flowering heathers. Take care not to trim back into old wood.
Soil preparation: Continue forking over the soil between shrubs, teasing compost into the surface. Prepare areas where summer bedding will be planted out in late May.
Roses: Complete rose pruning in March before they start into strong growth. Shorten all shoots, cutting back to an outward-facing bud.
Summer bulbs: Many summer-flowering bulbs can be planted in March and April. In mild areas, dahlia tubers can be planted outside, covered with about 10cm (4in) of soil. In cold regions, delay planting until later in April. In the coming months, plant groups of gladioli at intervals to extend their flowering season. Grow lilies in pots so that they can be moved into the garden to fill any gaps.
Boost your borders: If you have any gaps in borders you can drop in your blooming pots or aquatic baskets or they can be dropped into the top of an ornamental patio pot. A succession of these pots will provide blooms right through spring. Once flowering is over they can be moved from their prime location. Keep them well-fed and watered, and allow the bulbs to die down naturally. Look after them well and they'll reward you with more blooms next spring. Alternatively, you can sow quick-growing hardy annuals directly into the soil during April.
Spring bulbs: Mark any congested clumps that have flowered poorly with a label to remind you to lift and divide them later in the year. Give every clump of bulbs a thorough soaking with a liquid feed.
Snowdrops: Divide any congested clumps, spacing out the bulbs when replanting. Plant them fairly deeply, watering in well with a liquid feed.
Mulch: Spread a thick layer of compost or well-rotted manure as a mulch around established shrubs and along the base of hedges to help conserve moisture in the soil and keep down annual weeds.
Sweet peas: Sow sweet peas outside where you want them to flower.
In the Glasshouse
Time to get sowing: Sow tomato plants in a warm place for growing in unheated greenhouses or planting outside in early June. Also sow aubergines, capsicum, celeriac, peppers and celery. Cucumbers and melons can be sown in late April. Half-hardy bedding plants can also be sown this month in trays in the greenhouse or on window-sills. When the seedlings are large enough to handle, prick out into small individual pots or space out in seed trays. If bushy plants need more space, pot up on their own. Water regularly and feed weekly.
Hanging baskets: Plant up baskets with fuchsias and tender perennials, then hang them in the greenhouse to develop. See our guide to planting and planning a hanging basket.
Herb cuttings: Tip out pots of well-rooted cuttings taken last summer and pot them up separately.
Summer bulbs: Buy bulbs, such as eucomis and begonias, from garden centres to grow in pots for extra summer flower colour. A variety of dormant canna rhizomes are available from garden centres. Pot up into 15cm (6in) pots, grow on in a heated greenhouse and plant out in June. Plant begonias tubers in pots in the greenhouse. Always ensure the slightly concave surface of the begonia tuber is uppermost, and just cover with compost. Pot on as plants grow, feeding weekly.
Cauliflower: Prick out seedlings from earlier sowings, spacing them out in seed trays to grow on for planting out later in the spring.
In the Kitchen Garden
Crops to sow outdoors: Crops to sow outside or under cloches in March and early April include mangetout, broad beans, beetroot, lettuce, parsnips, onions, peas, spinach, radish, turnips and herbs. Sow Brussels sprouts, summer cauliflower and cabbage in a seedbed to transplant to final positions in May.
Onions leeks and garlic: Plant out onion sets and seedlings that have already been grown in modular trays. Grow them in rows, leaving space to get your hoe in for weeding. Plant out individual cloves of garlic, placing them about 5cm (2in) deep and 15cm (6in) apart. Sow leeks in a nursery bed outside. These can be transplanted in summer to their final rows. Shallots should already have been planted, but if not do so as soon as possible.
Growing bags: Compost-filled growing bags are an ideal way to grow a wide range of crops, from tomatoes and cucumbers to peppers, aubergines and melons. By using fresh bags each year, you can avoid the disease problems associated with growing crops in greenhouse border soil. There are many types of bag, with both peat-based and peat-free composts, some with added nutrients and wetting agents. Bring them into the greenhouse to warm up before planting.
Feeding fruit: Apply sulphate of potash or a general fertiliser around strawberry plants, fruit bushes and trees.
Pests and diseases: Some varieties of fruit can be regularly attacked by pests and diseases, from sawfly to mildew and scab. You can either leave plants to cope on their own or begin a spraying programme to prevent problems this year. Spot treat greenfly, especially on plum trees, before infestations go out of control and cause lasting damage.
Potatoes: Plant out early potatoes in late March, second earlies in early April, and maincrop varieties towards the end of April. Delay planting in very cold districts.
Give lawns a rake over: Months of wet weather will have caused moss to become a problem in many lawns. Thick moss quickly smothers out grass, so action is needed this spring to remove it, boost grass growth and improve surface drainage across the lawn. Chemical moss killers can be used to destroy existing moss, but this will still need to be raked out. Far better to use a powered lawn rake to scarify the lawn, raking out moss and debris. These can be hired for a weekend if you don't own one. Afterwards, fork over the whole area to improve surface drainage. Increase frequency of mowing as growth dictates. Later, in April or early May, apply fertiliser and check regularly for weeds, digging out any that you find.
Warming the soil: At this time of year, cold, wet soil can prove fatal to early sowings made outside. By covering prepared beds with cloches you will warm up the soil, protect it from hard frost and keep the rain off. Leave the cloches in place for a couple of weeks, then rake the soil surface before sowing seed or planting out young seedlings. Finally, put the cloches back over them to give your young plants a speedy start.
Weeds: Start spot treating lawns to get rid of any perennial weeds or moss. Hoe during dry weather to prevent weed seedlings establishing.
Restore soil nutrients:Months of rain through autumn and winter will have washed away a large proportion of the soluble nutrients in your soil. As soon as trees, shrubs, roses and hedges surge into new growth their roots will be searching for food, and this is an ideal time to provide it. Sprinkle a general fertiliser, such as blood fish and bone, pelleted poultry manure or something similar, over the soil between established plants. Where possible, hoe into the soil's surface. Clumps of developing bulbs and perennials also benefit from feeding during spring. Later in April apply a high-nitrogen feed to all lawns, too
Frost protection: Keep a few sheets of fleece handy to protect new shoots and blooms of shrubs when sharp frosts are forecast. Camellia and magnolia blooms can quickly become blackened by frost and the newly-emerging leaves of Japanese maples can be scorched. If conditions turn cold and frosty, move pot-grown shrubs to a sheltered position and wrap in protective fleece.
Slugs and snails: Watch out for slugs and snails. Trap them under tiles or grapefruit skins and dispose of them daily. Sprinkling a layer of sand, grit or crushed eggshells around plants may help. Alternatively, sparingly scatter slug pellets around plants most at risk. Never leave pellets in piles. Cover pellets with a tile resting on pebbles to keep them out of sight of birds and animals.
Plant supports: Place plant support frames over clumps of tall perennials so that new stems will grow up through them and hide them completely
Control climbers: Control the growth of climbing plants on walls of houses and outbuildings if they start to block gutters or grow under tiles. Cut them away from doors and windows too.
Revitalise your alpine garden: Whether you have a small alpine garden in a container or an impressive rock garden, now is a good time to clear away dead or overgrown plants to make space for new subjects. Garden centres offer a good range, from houseleeks to miniature shrubs like hebe, and they usually cost about £1.50 to £2 each, sometimes less. Improve the planting soil by digging in extra gravel to increase drainage. Then spread a mulch of gravel around the alpines after planting.