Gardeners with a penchant for tender plants have been reasonably lucky for the last few years. A succession of mild winters with little if any snow have meant that most tender plants have sailed through the cold season unscathed. Yet there’s always the risk that frost can bite when you least expect it.
1 Keep alpines dry
Growing at altitude in the wild, hardy alpine plants can shrug off frost and use a blanket of snow for insulation. Their real enemy in winter is heavy rain and boggy soil, which can make them rot. To keep them alive, protect them from rain by ensuring they’re planted in a well drained gritty soil and build them a small perspex shelter supported on columns of bricks, or use a plastic cloche with open ends so they can stay ventillated without getting their crowns wet.
2 Lift tender tubers
Plants such as dahlias, eucomis, begonias and gladioli have tender bulbs, tubers and corms that benefit from a deep mulch of compost topped with a layer of chipped bark in winter. In colder parts of the country it’s better to lift them before the frosts, shaking off any soil, cutting off the stems to 10cm (4in) and leaving them to dry for a couple of weeks. Then, store them in a frost-free place in a suitable plastic tray filled with compost.
3 Add a layer of fleece
Tender plants, rooted cuttings and young autumn crops can all be protected from frost, wind and hail by swaddling them with horticultural-grade fleece. This light weight and porous fabric allows the plants to receive the light, warmth and moisture they need to grow, but without making plants overheat or increasing humidity. Hold it in place using heavy stones or bricks, without dragging the plant down. Make a tent over taller plants using garden canes and pegs or clips.
4 Wrap up tender exotics
Tender exotic plants such as banana plants and tree ferns will die if exposed to freezing temperatures, so if you can’t pot them up and move them into a frost-free greenhouse or conservatory, it’s best to wrap them in a layer of fleece or hessian, with straw or polystyrene packed inside to protect their crowns. It’s best to get this protective layer in place by late autumn. During long period of warm weather the ‘duvet’ should be removed to prevent the plant from sweating and possibly rotting.
5 Protect patio pots with bubblewrap
Plants in containers are specially vulnerable to frost damage as their roots don’t enjoy as much insulation as they would if planted in the ground. Wrap the pots in a duvet of bubblewrap and hide it with a layer of hessian and twine for a more aesthetically pleasing look on the patio. Don’t forget that terracotta pots are porous, so ensure they stay well drained by setting them on pot feet.
6. Lay a mulch
Adding a thick 10cm (4in) mulch around the bottom of a shrub, or over the top of a dormant perennial plant underground, can insulate the soil and keep its roots, tubers, bulbs or corms from freezing. Useful organic mulches (which will rot down in time, adding nutrients to the soil) include bark, garden shreddings, compost, well-rotted manure, grass clippings, newspaper, leafmould and straw.
• Don’t feed plants with nitrogen-rich fertilisers late in the season as this encourages them to put on frost-vulnerable sappy growth
• Work out where your warm and sheltered spots are in the garden and group container plants in these positions over winter
• Plant early-flowering magnolias and camellias in a north or west-facing site so they’re protected from early morning sun on frosty days
• Invest in cloches and fleece for nights when frost or snow are forecast - all small plants will appreciate the extra insulation
• Knock snow off shrubs and hedges as the extra weight can snap branches
1. Spruce up borders - There can be a strong urge to cut back garden borders at this time of year, but resist being too tidy. Leave anything that has attractive seed heads, seasonal colour or berries as these will create interesting silhouettes in the low autumnal light, catch the frost and provide food and shelter for wildlife. Instead take your secateurs to soggy foliage flopping onto paths, as this can become a slip hazard, and anything that is dying an unattractive death.
2. Order bareroot roses - Planting bareroot roses is more cost effective than buying them as container-grown plants; they also tend to establish more quickly. Bareroot roses are only available from November to March as the plants need to be dormant when they’re despatched by the nursery. The best time for planting is late autumn before the ground is frosted or waterlogged, so order now to ensure delivery in time.
3. Make leaf mould - Decayed leaves are generally low in nutrients but they’re fantastic for adding organic matter, which improves the structure and water-retaining properties of soil. Leaves tend to break down more slowly than other vegetation, so it’s best to compost them separately. Either rake or gather up the leaves and store them in plastic rubbish bins with holes drilled in the base and sides to allow for drainage and air flow or fill black bin liners and use a garden fork to make some holes, or make a cage for them using wooden stakes surrounded by chicken wire.
4. Lift or mulch dahlias - Lifting and storing dahlias over winter is the best way to ensure they’ll survive. Wait until the first frosts have blackened the foliage, then cut the stems down to the ground. Carefully lift the root ball and remove as much soil as possible from around the tubers. Store the tubers upside down somewhere dark, dry and frost-free for a couple of weeks to allow any moisture to drain away. Brush away any remaining soil, wrap in newspaper and pop them in crates or trays over winter in a well-ventilated, frost-free place to prevent rotting.
5. Take hardwood cuttings - Hardwood cuttings are an easy way to propagate a whole host of woody climbers, trees and shrubs. Choose long, healthy, vigorous shoots from this year’s growth, about the thickness of a pencil. Use secateurs to remove the shoots above a bud.
Remove the soft tip then, cut into sections about 20cm (8in) long. Cut above a bud with a sloping cut. This will allow water to drain away and also indicate the top of cutting. For the bottom of the cutting cut just below a bud with a straight cut. Put them in a well-drained compost. Fill deep containers with a free-draining compost mix – 50:50 compost and horticultural grit. Push the cuttings in around the edge leaving one-third above the surface of the compost. After watering, place them in a cold frame, cold greenhouse or a sheltered spot. Leave them in their pots until the following autumn, making sure they don’t dry out in the meantime. Once they’ve rooted, pot on into individual containers.
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1. Clean out the greenhouse - By the middle of the month any crops in the greenhouse will be unlikely to ripen any further. Pick what you can then take this opportunity to clean out the greenhouse. Wipe the glass to remove any dust and dirt to maximise any light entering over the coming months. Wash the internal framework and staging, and sweep the floor of any debris to get rid of any pests and diseases. This will give you a pristine greenhouse that will be the perfect home fortender or borderline hardy plants over winter.
2. Plant spring bulbs - No garden should be without the burst of cheerful spring colour that bulbs provide. Daffodils are the classic spring bulb, but there are so many more to choose from, whether it’s muscari, scilla, ipheion, chionodoxa, leucojums or a whole range of fabulous fritillaries. And now is the perfect time to plant them. Pop them in the ground, or in pots, three times the depth of the bulb with the pointy end upwards.
3. Naturalise bulbs in grass - For a naturalistic way to grow bulbs in the garden, plant them into grass. This needs to be an area of grass that can be left to grow in late spring and early summer until all the foliage from the bulbs has died down, rather than a patch of pristine lawn. Bulbs that are ideal for naturalising include our native daffodil Narcissus pseudonarcissus, snake’s head fritillaries and crocus. Either use a trowel or abulb planter to remove a section of grass and soil, drop in the bulb, then fill the hole back up with the soil and replace the grass.
4. Look after your lawn - Now's the perfect time to get your lawn back into shape after summer. Rake out the thatch – dead grass and moss - that will have built up. Use a fork to aerate the lawn, apply a top dressing of sand to improve drainage and brush this into the holes you’ve made with the fork. Scatter a lawn fertiliser, but make sure you use an autumn fertiliser that is low in nitrogen as you don’t want to encourage lots of lush growth at this time of year.
5. Divide early-summer flowering perennials - It might be getting chilly on a morning but because soil holds on to warmth longer than air now is a great time to divide some perennials. At this time of year it’s best to divide just spring and early summer-flowering perennials that need rejuvenating, such as hardy geraniums and Alchemilla mollis. Generally these plants need dividing every 3 or 4 years. Later-flowering perennials like rudbeckia and heleniums and most grasses don’t like their roots to be disturbed at this time of year. If they need dividing they should be left until next spring.
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1 Look after strawberries - once they've finished fruiting, cut back the leaves to about 10cm (4in) above the crown. Remove any foliage lying on the soil, which might harbour diseases, and cut away any unwanted runners. Apply a general-purpose fertiliser (such as Growmore) and give the plants a good watering.
2 Give evergreen hedges a trim - young birds should have fledged by now, so use this opportunity to give evergreen hedges a trim. This will allow any new growth time to harden up before winter and will give a crisply-edged structure throughout autumn and winter.
3 Feed baskets and containers - flowers in containers and hanging baskets will need a helping hand over the coming weeks to keep them blooming. Feed with a liquid fertiliser high in potash (such as tomato feed) once a week for an instant boost.
4 Watch for blackspot - warm, humid August weather is perfect for the fungal disease blackspot to thrive. It causes black patches to form on the foliage of roses, which then wither and fall. In the worst cases roses can be left completely bare. To stop it spreading, gather up any infected leaves that fall, and apply a chemical fungicide spray (such as RoseClear Ultra Gun £4.99 for 1L spray), or, for an organic method, try spraying with a mixture of one part milk, two parts water.
5. Take ‘insurance cuttings’ of tender perennials - pelargoniums and certain salvias will need to be given protection if they’re to survive the winter. Now’s the time to take softwood cuttings so you have a supply of new plants for next spring.
How to do it:
• Pick the right stems. Remove a few healthy, non-flowering stems from the plant – they should be about 10-15cm (4-6in) long. Morning is the best time to do this as the stems and leaves are full of water and the plants at their least stressed. Remove the cutting above a set of leaves with sharp clean secateurs and pop it into a plastic bag.
• Prepare the shoots. Trim each cutting to just below a set of leaves and then create a clean stem by removing the bottom third of leaves.
• Plant the cuttings. Pop them around the edge of a pot filled with a 50:50 mix of compost and perlite (or, seed compost will do). Label, water and place the pots somewhere warm but out of direct sunlight.
• Grow them on. Plant up into individual containers when roots appear at the bottom of the pot.
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Keep on top of late summer borders, containers and hanging baskets by deadheading, watering and weeding.
1. Top up ponds – In warm summer sunshine the water in a pond will evaporate, so keep the water levels topped up. If you can, use collected rainwater, if not let tap water stand for a few hours to allow some of the chemicals to escape.
2. Raise the height on your mower – In dry spells grass can be put under stress and mowing too short can lead to scorched patches. Raise the height on your mower (no lower than 4cm/1 ½in) and leave the grass a little longer.
3. Order spring bulbs – It might seem odd to be thinking about spring but if you want the best selection of bulbs now is the time to get your orders in with specialist bulb suppliers.
4. Last chance to sow biennials – If you didn’t get around to sowing biennials last month you’ve still got time – just! Sow sweet william, Canterbury bells, sweet rocket and foxgloves in the next week or so for flowers next spring and summer.
5. Pinch out cordon tomatoes – To concentrate the energy of cordon tomatoes into fruit production pinch out any side shoots that form.
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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