Keep your garden looking neat and sweet with these timely reminders.
1. Sow biennials Biennials are plants that are sown one year, then flower the following spring or summer. They’re fantastic for combining with spring-flowering bulbs and often make great cut flowers too. Sow the seed into trays filled with multipurpose compost and follow the instructions on the seed packets as to whether to cover the seeds or not. Water, label and place somewhere bright but out of the heat of the midday sun. Seedlings can dry out quickly at this time of year, so water regularly. They’ll be ready to prick out in a couple of weeks.
2. Trim box for Derby Day The traditional time to cut back the new growth of box and create crisp lines for your topiary is Derby Day (the first Saturday in June) but any time this month is fine. Put an old sheet around the base of your box plants to catch the clippings and make tidying up easier. Afterwards, water around the base of the plant, and try to avoid splashing the foliage.
3. Cut back early-flowering perennials Some spring-flowering perennials such as geraniums and oriental poppies may be looking a little tired by now, so cut back any growth to just above the crown of the plant. Give them a good water and a feed and you might even get a second flush of flowers.
4. Deadhead roses Keep repeat-flowering roses looking good and encourage more flowers by removing any dead or fading blooms. You can snip these off by cutting back to a leaf joint, or simply snap off the old rose head at the bulbous bit behind the flower where it joins the stem.
5. Make comfrey feed If you have a patch of comfrey now is the time to make a batch of homemade liquid plant food. Comfrey is high in nutrients that will help your plants to flourish. Wear gloves and a long-sleeved top to cut an armful of leaves. Pop them into a large bucket, fill with water and cover. After four weeks the brew will be ready to use – it’s a bit smelly. Remove the decaying leaves and pop them on the compost heap. Dilute the feed in a watering can, using one part comfrey liquid to ten parts water.
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The risk of frost has usually passed by the end of May, so it’ll soon be safe to start planting tender and half-hardy plants outdoors without protection. For now, while hardening off tender seedlings, keep some horticultural fleece to hand in case frost is forecast.
1. Keep floppy annuals and perennials upright by putting in supports and stakes now. Their foliage will quickly grow to hide the framework. For a more rustic look, use hazel sticks or other straight branches from the garden.
2. Temperatures in protected glazed areas such as greenhouses and conservatories can get very hot in May. Watch that delicate plants don’t become scorched or overheated by keeping vents or windows open during the heat of the day and closing them again at night. Take care with watering too.
3. Prune shrubs and climbers that have already flowered for spring. Examples include Clematis montana, Kerria japonica, and spirea ‘Arguta’.
4. Trim formal evergreen hedging such as box, making sure no birds are nesting in it first. Small-leaved box will become more dense with pruning, helping to create crisp green topiary edges.
5. Watch for the slow build up of pests in the garden. Aphids start to become more active in late spring, and molluscs such as snails and slugs will start to take fresh interest in any seedlings. Use insecticides carefully and avoid spraying flowers in bloom as this can lead to harming beneficial pollinators.
As the days get longer and warmer, April showers will keep newly established plants watered. There’s still a risk of frost until the end of next month, so it’s too early to plant out tender seedlngs.
1 Get sowing! In mild areas, many hardy annuals can be started off outdoors in April. Sow them directly where they are to flower in a well prepared seedbed, or sow in pots or modules inside to transplant next month.
2 Apply mulch around perennials. A deep layer of well-rotted organic matter (5-8cm/3-4in) will help nourish the soil and hold moisture in. Remember that garden compost and rotted farmyard manure may not be completely weed free so watch for germinating weeds and hoe them off on a dry day.
3 Add plant supports. Floppy herbaceous perennials may need staking in the border, so add supports now so the plants can hide them as they grow. It’s far easier to stake now than later. Tie in whippy new climber stems to trellis too.
4 Repair bare patches in the lawn. Prepare the bare soil by scuffing it over with a hand fork, then sow a handful of fresh grass seed on top. Cover with a light sprinkling of compost. Keep the area just moist to help the seeds germinate and protect the seed with an upturned hanging basket or similar to keep hungry birds off.
5 Look out for signs of pests and diseases. It’s better to spot pest damage now and take preventative measures before the problem builds up. Where possible use an organic solution – removing aphids and slugs or caterpillars by hand (wear a rubber glove) rather than using pesticides, which can harm pollinating insects and beneficial wildlife.
Prepare the garden for the coming season by sowing seeds, tidying and pruning – but watch you don’t cut off emerging flower buds on perennials or shrubs that will flower in spring and early summer.
1 Deadhead daffodils. Snap or cut off the faded flower and seedpod to keep the display from looking jaded. Don’t cut back the foliage – let it die back naturally so the leaves can keep photosynthesising. This way they can convert solar energy into complex sugars that will nourish the bulb for next year.
2 Prune roses. This will encourage strong new growth. Use sharp secateurs to cut out any dead, diseased, crossing or damaged stems and cut just above an outward facing bud, so new growth will grow away from the centre of the plant. Cut back shrub roses to about 30cm (12in) to rejuvenate them.
3 Move deciduous trees or shrubs. Now the soil is warming up it’s safe to move dormant plants to a new home if need be. Make generous planting holes and add plenty of nutritious organic matter before filling in. Tread down the soil well to ensure good contact and water well. Don’t move plants if the ground is waterlogged or frozen.
4 Start chitting potatoes if you haven’t already. Place seed potatoes on a bright and airy, frost free windowsill so they start to produce shoots. Position them in an empty eggbox if possible, rose end uppermost (the end with most eyes). In 6-8 weeks the potatoes will have started sprouting and it’ll safe to sow them outside.
5 Tidy lawn edges by re-cutting them with a half-moon edger. Mow if your grass is looking shaggy but choose a dry day and keep the blades on a high setting.
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1. Lift and divide snowdrops in the green: It’s safe to lift snowdrops once they’ve finished flowering and their foliage has begun to yellow. Split the clumps into smaller clumps but avoid tearing the roots. Replant the bulbs singly at the same depth as they were before.
2. Prune summer-flowering clematis: It’s time to prune Group 3 clematis – those that flower in late summer and autumn. Choose a calm, frost-free day before the plant has started into active growth. Cut them back to a pair of strong buds about 20cm (8in) from ground level, removing all the previous year’s growth.
• You can also prune Group 2 clematis (those that produce large flowers in summer) but don’t prune as hard as you’ll remove flower buds developing on last year’s stems. Instead just remove damaged, diseased and weak stems, cutting back to a healthy pair of buds.
3. Cut back deciduous grasses: Remove spent stems with sharp secateurs, taking care not to damage any new green shoots that are emerging. Top dress with a general fertiliser to nourish the plant roots. Deciduous grasses include calamagrostis and deschampsia. With stipa, simply comb out the older growth with your fingertips.
4. Chit potatoes: Give seed potatoes a head start on the season by chitting them on a bright, frost-free kitchen windowsill. Place the seed potato with its rose end (with lots of eyes) upwards in an egg box and leave it to sprout. The potatoes will be ready to plant out in about 4-6 weeks, once these new shoots are about 3cm long.
5. Check for hellebore leaf spot: This is caused by a fungus and is quite common, attacking most hellebore species. Watch out for round, dead, brown patches on leaves and stems and remove and destroy affected leaves promptly.
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Keep the garden looking its best this month by planting up pots of winter-flowering bulbs, pruning dormant shrubs to tidy them and cleaning tools and pots so you're ready for spring.
1 Make cuttings of cornus stems: Select a stem that grew last summer and cut it from the base of the shrub. Trim the stem into sections each about 15cm long, with a bud at each tip. Use a sloping cut to shed the rain (it will help you remember which way is up). Trim the base of each cutting squarely across the bottom just under a bud or pair of buds. Plant them out into a narrow trench on a mild day when the soil isn't frozen. Place each stem about 15cm apart with one third of the stem sticking out about the soil level. Cover over to close the trench.
2 Avoid walking on the lawn: During frosty weather it's best to keep off the lawn as walking on it can damage the grass and leave brown footprint-shaped marks. The grass will grow at temperatures above 5C (41F) so you may still need to mow the lawn during a warm spell.
3 Feed the birds: Garden birds rely on us more and more to support them through the winter with supplementary feeding. Top up bird feeders with nuts and oil-rich sunflower seeds. Use a fat ball dispenser to feed them fat-rich suet snacks; the green mesh bags can trap their feet.
4 Winter-prune wisteria: To get the best flowers wisteria need cutting back twice a year and January is the ideal time to give them their winter prune. Cut back all the stems from this year's growth to two to three buds, except where you need growth to extend the framework of branches to cover the support.
5 Clean pots and trays: If you've got a big pile of dirty plastic pots lurking in your potting shed now's the time to address them. Fill a large bucket or plastic true with warm soapy water and use a pot scrub to loosen the dirt. Rinse with running water.
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