Timely tasks to carry out in the garden this month including bulb, tree and shrub planting
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| Many bulbs are ideal for containers
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'This is the main time for planting bulbs, so try to complete all your bulb planting this month.'
Alpines
Although most alpines are planted in spring, you will get a far better display if you plant them in autumn so they will have time to establish and make some growth.
Bearded iris
Bearded iris need attention now to prevent the leaf fans rotting in winter. Pull away vegetation to reveal the base of the leaf fans and rhizomes and cut away any dying foliage, or leaves with fungal leaf spot – this disease thrives in wet, autumn conditions and can destroy most of the leaves.
Bedding plants
Now is a great time to pull up summer bedding and replace it with plants for a spring display. Although it may seem heartless to do this to your summer plants, you need to get the spring plants in now, while the soil's moist, so that they can grow and establish before winter.
I like to fork in as much organic matter as I can find at this time of year, emptying the compost heap first so I can put all the summer bedding in its place – but having two or more compost heaps, or lots of big pots, makes this easier.
Wallflowers are beautiful and fragrant in flower, and available now. These are useful, and inexpensive, for large areas. In smaller areas I like to us pansies, Bellis (double daisies) and forget-me-nots. Save some money to buy bulbs too – I use lots of hyacinths because I find these can be kept for several years if lifted and dried carefully. And I treat myself to tulips for those special places – the taller kinds are essential with wallflowers. Put the wallflowers in first, then add the bulbs.
Bulb planting
This is the main time for planting bulbs, so try to complete all your bulb planting this month. It's surprising how early bulbs, such as daffodils and hyacinths, will begin to produce roots if they are left in the soil – and the secret of good flowers is the establishment of roots. The smaller bulbs and corms, such as
Chionodoxa and
Crocus must take priority, followed by daffodils and fritillarias, while tulips can be left until last.
Paperwhite daffodils are the easiest bulbs to grow for the festive season and can be planted in soil, or just water and gravel. Unlike most bulbs, you can plant them in a light spot to grow without special cultivation. In warm conditions they will flower in less than two months after planting, so keep them cool if you want flowers for Christmas.
You can plant stored lily bulbs in the garden now, or in pots if your soil is heavy. Autumn planting is kinder to the bulbs, which dry out when lifted and stored.
Dahlias and gladioli
Once frost has blackened the foliage, lift your dahlias and gladioli. Cut dahlia stems, leaving about 10cm (4in) of stem, and leave the tubers to dry off on the greenhouse bench. Cut gladioli stems to the same length, snap off and discard the old, shrivelled, lower corm and save the fresh corms (and any tiny cormlets) to increase your stock.
Dividing herbaceous perennials
Herbaceous perennials are usually divided in spring, just as they're starting to grow, but you can effectively split and replant them in autumn. The advantage of this is that the soil is warmer than in March and the task is much more pleasant.
Dividing is also useful for plants that flower early in spring, such as doronicums, hellebores and pulmonarias. The exceptions to autumn division are plants that are slightly tender, such as agapanthus and ornamental grasses such as Miscanthus – both can be left until spring.
Frost protection for plants
There's no need to wrap your cordylines yet, but you should move truly frost-tender plants into the greenhouse. Fuchsias and dahlias can be left until their top growth is touched by frost, but bananas, lantanas and pelargoniums will fare better without frosting.
Once frost has touched plants such as Agapanthus, that will spend winter outside, cut off frosted leaves and cover crowns with a protective mulch. Bracken or straw is ideal, but can blow away, so cover it with fleece or netting pegged down. Avoid plastic, as this prevents air reaching the crowns and may cause rotting.
Move plants in pots, such as Agave and Cordyline, to the house wall for protection. This also applies to otherwise hardy plants, such as Camellia, because the soil in the open garden can become frozen and kill plants.
Greenhouse plants
A few plants in the greenhouse that have made a colourful display will be past their best now and should be added to the compost heap.
Celosia,
Coleus and
Torenias grown from seed are all candidates for composting. Other plants, such as
Achimenes,
Begonia and
Gloxinia can be stored for next year if dried off carefully and kept at a temperature of about 10ºC (50ºF) in winter. You can keep
Coleus grown from cuttings for next year, but they need a winter temperature of 10ºC (50ºF) and are not easy plants to keep in the greenhouse.
Lathyrus odoratus (sweet peas)
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| Sow sweet peas this autumn
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The best sweet peas, and the earliest crop of flowers, is obtained from those sown in October. At this time of year they do not need artificial heat, germinating well at about 10ºC (50ºF). Sow three seeds per pot and plant out in a clump in March. Once the seeds have germinated, keep young plants moist in a cold frame or cool greenhouse. Protect them from mice, which relish the seeds, in winter.
Lawn weeds
Even after an application of lawn weedkiller, some weeds will survive and, at this time of year, new weeds may germinate in any bare patches. Worm casts are a problem in autumn and, if you do not brush these off the lawn before mowing, they can get squashed onto the turf and form ideal seedbeds for weeds.
The most destructive weeds are those that form rosettes and smother out the grass, including dandelions, plantains and thistles. A mass of plantains covered large areas of my new lawn, sown in early summer. As lawn weedkillers shouldn't be used on new lawns, I cut them out with a knife – avoiding the unsightly appearance of many weeds dying.
Houseplants
Put houseplants in the shower to wash off dust. Add some more compost if the pots need it, and give the leaves a clean and polish with some leaf-shine wipes (but only apply these to plants with waxy, thick leaves). Do not use household polish or milk, as this will block the pores in the leaves. You can clean hairy-leaved plants, such as African violets, with a small paintbrush. Water less now and you should not need to feed until spring. Repot houseplants in spring.
My favourite fragrant houseplant is Gardenia – nothing compares to the rich, soapy smell. But I have never had much success with them: they either go yellow and end up looking like bare sticks, or they succumb to red spider mite, after which I am afraid they have to go in the dustbin. However, the addition of my conservatory, which is shaded for most of the day, has meant success, and the plant carried dozens of flowers all through summer.
I allowed it to get quite dry between waterings, and it wilted sometimes, much to my horror. But it kept at least a few flowers for many months. I feed it once a week with Baby Bio and am quite proud of the results.
Mulching
Mulch borders around perennials and under shrubs to suppress weeds and improve soil. If you leave this until after bulbs have been planted, you'll damage young bulb shoots as you spread the mulch.
Patio plant: Brugmansia
Brugmansias are my favourite patio plants. They grow rapidly, the large flowers are always dramatic and the fragrance is heady, especially in the evening. Under glass they suffer from red spider mite, but this is less of a problem outside.
My variegated plant has lovely leaves and apricot flowers. They tend to want to produce their blooms in flushes but, if they are well fed, they will bloom continuously. I water my plant every day and apply liquid fertiliser twice a week, plus a boost of seaweed extract once a week.
Things are coming to an end now and I will move the plant into the greenhouse to keep it frost-free. It will lose most of its leaves, but I will not prune until spring because pruning in autumn and winter leads to die-back. I will repot it in spring too, removing some of the new, young growth for cuttings.
Planting trees and shrubs
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| Dig a large hole and add a stake to secure a newly planted tree
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Autumn is the best time to plant trees and shrubs while the soil is warm and moist. You can plant pot-grown shrubs all year, but in summer it's hard to keep them watered as they start to establish. In autumn you can also buy bare-root trees and shrubs by mail order, or from nurseries, often at cheaper prices than pot-grown plants.
Do not skimp on soil preparation. Dig a large hole so that you can add plenty of organic matter around the plant's roots, then stake the plant well to prevent winter gales rocking the plant and damaging roots (wind rock). Wait until spring, when the plant starts to grow, to apply fertiliser.
Ponds
I hate having to clear out evil-smelling gloop from the bottom of the pond, but now is a good time to tackle the job, before too many creatures retire to the mud for winter. Also, cut back any decaying foliage from water lilies and marginal plants, and net the pond if it's near overhanging trees to reduce the amount of foliage that falls into the water. If you do use a net, take care to ensure that hedgehogs and frogs do not get caught in it.
Potting up rooted cuttings
Cuttings of
Fuchsia,
Pelargonium,
Plectranthus and other tender plants that were taken in late August and September should have formed good roots by now and you can pot these young plants up into small 8cm (3in) pots. These plants will have time to fill the compost with roots before the onset of winter.
Seed collecting
If the weather is dry and fine you can continue to collect seeds from your plants. Lay the seed pods on newspaper in a dry, airy place, and when the seeds have dropped out or have been removed, store them in labelled paper envelopes.
Sowing hardy annuals
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| Sow hardy annuals like Nigella
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In mild areas you can still sow hardy annuals to flower early next summer.
Calendula,
Nigella and
Limnanthes are among the easiest.
Trimming shrubs
You can trim fast-growing shrubs, such as
Buddleja,
Lavatera and tall roses, lightly now. This makes them tidy and, by shortening their height and removing most of the foliage, reduces damage caused by winter gales. Don't prune them fully as this stage, however, as this may encourage new growth which is liable to be damaged by winter frosts. Lavatera is particularly prone to storm damage and the large stems often break off if left unpruned.
Window boxes
I like to make my window boxes special, and rather than use simple bedding plants, I pack them with evergreen shrubs and herbaceous plants, as well as bulbs. I use them almost as nursery beds because the perennials can be taken out of the window boxes in late spring and used in the garden.
Suitable plants include carex, conifers, euonymus, small hebes, heathers and ivies, with the addition of some colourful bulbs. Window boxes are usually rather sheltered from extremes of cold, so it's worth experimenting with some tender plants such as the small cyclamen hybrids, solanums and winter kales. These may not last much beyond the new year, but they can then be replaced with pansies for spring colour.
*For more on bulbs, practical tasks and jobs for the month, see Related Articles at the bottom of this page.
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