Saving plants from the winter chill

By Hannah Stephenson

I looked out on my patio a few days ago to see a pelargonium I planted back in May coming into flower yet again, at a time when most of my summer pots have been emptied.

Despite a lot of rain, it's been a mild October, and this may lull many of us into a false sense of security about how long we leave it before offering our plants some protection from the winter chill.

As I live in a frost pocket, the pelargonium is going to come under cover soon. If you have pots of pelargoniums (bedding geraniums) which you want to enjoy next year, put them inside too, in a light, frost-free place such as a slightly heated greenhouse, a sheltered porch next to the house or an unheated spare room or conservatory, cutting them back to 10cm (4in). Don't expose them to warm central heating or they'll just wilt when you put them out next year.

Fuchsias, which lose their leaves entirely and spend winter looking like bare sticks, will need the same treatment. You'll hardly need to water them at all until growth resumes in spring, at which point you can repot them into John Innes No 2 potting compost and harden them off before placing them outside when the risk of frost has passed.

Marguerites (Argyranthemums) will also not stand any frost and are best dug up and potted, cut back by half and kept in a dry, cool, frost-free place that has sunlight through the winter, like a cool greenhouse. Water them sparingly to keep their roots dry until spring, when you can start to water them more frequently.

If your garden has a Mediterranean theme, you're likely to need to protect other vulnerable plants, such as cannas, olive trees, ginger lilies and dahlias, which may not survive winter frosts.

Leave dahlia tubers in the ground until the foliage has been blackened by frost, which may be as late as November, then cut the plants down to around 15cm (6in) from the ground and dig up the tubers. Shake off the soil, wash the tubers and turn them upside down so the moisture drains out of the hollow stems. When they've dried off, hang them in nets in a shed or store them in stacking trays with plenty of holes for ventilation.

Cannas need to be cut down before winter and mulched heavily, or dug up and put into pots only slightly bigger than their ball of roots, filling the gaps with compost, and kept in a frost-free place, ideally under the staging in a greenhouse.

If you don't have heating in your greenhouse, insulating your more tender plants with bubble wrap can make a huge difference, especially if you buy the fixing clips which separate the glass from the bubble wrap, creating a thin pocket of insulating air between the glass and the wrap. Alternatively, you may have to venture out on really cold nights and cover your tender specimens with horticultural fleece to keep the winter chill at bay.

Other plants that form tubers such as ginger lilies are best dug up at the end of the season, the top growth cut off with secateurs and then the tubers stored until spring in dry potting compost in a cool, frost-free place like a garage or shed. They can be planted out next year when all danger of frost has passed.

Pots of tender exotics such as citrus, palms and oleander which have graced your patio in summer will need to be moved back under cover, either into a cool conservatory or frost-free greenhouse, and will need to be watered sparingly throughout the winter. If your tender plants are simply too big to move, then wrapping them in hessian or horticultural fleece may be the answer.

Other tender plants such as cordylines, Pittosporum tobira and cestrum, callistemon and Clerodendrum bungei may need wrapping, by framing the plant with a wigwam of bamboo canes and then packing the base of the plant with straw and wrapping the cane frame with horticultural fleece.

Banana plants can either be heavily mulched to protect the roots, so growth starts again from soil level in the spring, or the top leaves cut off and the whole plant stem wrapped in straw, secured with chicken wire or hessian, so the plant can still breathe.

Hopefully, a bit of TLC over the winter months will ensure that your plants are brought back to their full glory next summer.

Best of the bunch - Katsura tree (Cercidiphyllum japonicum)

If you want a bit of wow factor in your garden in autumn, look no further than the Katsura tree, or candyfloss tree as it is sometimes known, which showers you in a sea of yellow, pink, orange and red leaves as autumn progresses. The delicate, heart-shaped leaves have a sweet caramel scent when they fall. It's a big tree, although it takes a long time to grow to its optimum height, 18m (60ft). It is also wide-spreading so might be more suited to larger gardens, although there is a fairly compact variety C. magnificum, which you may have to seek out in specialist nurseries. The Katsura tree is an ideal choice for sheltered woodland gardens on acid soil, as it prefers fertile, well-drained lime-free soil with plenty of organic matter and can be planted among other mature trees which will give it protection from cold winds and frosts that can damage the emerging foliage.

Good enough to eat - Autumn cauliflower

You should now be picking autumn cauliflowers which have formed a good-sized head. These create delicious cauliflower cheese or you can use them raw in salads, or as a crudite for dips, or you can even add them to pickles for Christmas. Autumn varieties, which range from large-headed types to more compact Australian-bred ones, should be sown outdoors between mid-April and mid-May and transplanted in late June. Choose a sunny spot where the plants will grow to maturity and work in plenty of compost the previous autumn to improve the soil's moisture-holding capacity. Sow the seed very thinly in 1cm deep drills in rows 15cm apart and cover with soil. Thin them to around 8cm apart and transplant them when they have five or six leaves, watering the rows the day before you move them to their permanent quarters. Cauliflowers need firm soil so don't fork over the surface before planting the seedlings. Make sure the soil is moist throughout the growing season and bend the uppermost leaves over the developing curds to protect them being discoloured by direct sunlight or damaged by a severe frost. Cut the heads when they are still small, before the curds start to separate.

Good varieties include 'Autumn Giant', a well-known and respected maincrop cauliflower with large dense white curds which are thoroughly protected by the leaves, and 'Barrier Reef', whose compact heads are ready for cutting in late October.

New products

Nature's Feast has launched a new range of innovative seed blends to help customers get even closer to the birds in their garden. The Everyday 4 Seed Blend, Supreme 8 Seed Blend and No Mess 12 Seed Blend have been developed to help attract the widest variety of wild birds into the garden, including woodpeckers, dunnocks, collared doves and chaffinches.

Each of the pack trio has different energy ratings, which increase depending on the number of oil seeds contained in each pack. The makers say that the higher the number of seeds in the blend, the wider variety of bird species it will attract.

The introduction of the new blends follows months of research, including the development of the company's Optimum Foraging Study. This was the only study of its kind to be undertaken by a bird seed manufacturer, identifying the feeding preferences of British birds, and allowing the brand to refine its blends. Priced from £2.99, the blends are available in garden centres, supermarkets and pet stores. For stockists call 01377 200 800.

What to do this week

:: Clear fallen leaves and recycle them to make leafmould.

:: Collect plant supports and canes to store for winter.

:: Fork over the soil between plants in established borders to loosen the surface. Remove weeds then spread on a layer of well-rotted compost.

:: Rake and scarify lawns removing thatch and accumulated debris.

:: Propagate hedging varieties of conifers from cuttings, using shoots of the new growth. Root directly into gritty soil in a cold frame.

:: Sprinkle fertiliser over areas to be planted up this autumn.

:: Clean and tidy established strawberry beds, removing weeds and any runners growing between rows.

:: Cut all ferny asparagus shoots down to soil level.

:: Sow sweet peas in deep containers in cold frames.

:: Continue to plant out wallflowers, primulas, forget-me-nots, pansies and other bedding plants for spring displays.

:: Top-dress lawns with a layer of gritty loam-based compost.

:: Finish potting on rooted cuttings and seedlings in the greenhouse.

:: Remove pond pumps and filters for winter storage.