12 urgent October jobs to protect your garden over winter

1. Plant now for a burst of winter colour

There’s nothing better than planting containers of late-winter-flowering bulbs right now, while imagining the cheerful display that will emerge early next year. I love to plant Iris reticulata in pots by the front door, where their exquisite blooms can be enjoyed as we come and go.

We grow Iris ‘Harmony’ with its glorious royal blue flowers, alongside the deep purple blooms of Iris ‘Pauline’. Iris ‘Katherine’s Gold’ and the muted blue tones of Iris ‘Alida’ create a softer combination. For a really unusual look, plant Iris ‘Frozen Planet’, whose pure white flowers have fall petals tinted with the palest blue. These diminutive irises are perfect for shallow containers and we also grow them in our green roof where the delicately patterned flowers are at eye-height.

2. Feed the soil and protect your plants

Once crops are harvested, cover bare soil with an autumn mulch of organic matter to protect the ground, retain heat and moisture, and prevent the loss of soil nutrients. Biodegradable mulches include garden compost and leaf mould, both of which should be applied to a depth of around 5cm. As you mulch around the base of plants, avoid covering the crown of perennials and don’t let mulch touch the stems of woody plants to avoid rotting.

Mulching in autumn also adds more worms and microorganisms to the soil. Worms will take the organic material down into the soil, improving the structure. Soil microbes recycle and store carbon deposited by living and dead plants, and they provide food for invertebrates such as beetles, springtails and nematodes. In turn, these animals provide food for birds and other garden wildlife.

3. Give elephant garlic a head start before winter

October is an ideal time to plant elephant garlic as this relative of the leek requires a long growing season. Place individual cloves pointy end up, 10-15cm deep and 20-30cm apart, into well-prepared weed-free soil. Keep well-watered and, by early summer next year, the bulbs should be ready to harvest.

Elephant garlic is easy to grow and has a mild taste. It was one of our family favourites when my children were young and I began to introduce them to spicier foods. It’s also easy to grow, provided it doesn’t sit in waterlogged soils overwinter. We grow it in large containers as, unfortunately, our soil had onion white rot several years ago, so we’ve been keeping it free of plants in the onion family for eight years in the hope that we’ll beat the fungal disease. Elephant garlic is a skin irritant and is toxic to pets.

4. Let nature feast on your fallen fruit

Fallen apples can be a delicious source of food for a range of garden wildlife during the autumn. Late-flying butterflies like red admirals are sometimes attracted to the sweet juice on sunny autumn days when nectar is scarce. Windfalls also lure in winter thrushes such as redwings and fieldfares that have been arriving from Scandinavia over the last few days.

Look out for these attractive thrushes on lawns, feeding on fruit and worms, or in your trees and shrubs where they are likely to be feasting on autumn berries such as rowan and hawthorn.

5. Turn fallen leaves into wildlife havens

In autumn, as trees stop producing chlorophyll in their leaves and withdraw any remaining green pigment, the fiery orange carotenoids, red anthocyanins and yellow flavanols in the leaves are revealed. Make the most of this free, natural resource this month by sweeping leaves from ponds, lawns and gravel areas into piles to create shelter for hedgehogs, frogs, toads, beetles and other invertebrates.

A few years ago, a hedgehog gathered leaves in our garden to make a domed nest beside our French windows in which it hibernated. Now I welcome autumn leaf fall as I know the dead and decomposing leaves provide so many resources, both for detritivores to eat and for other animals to use for shelter and warmth in the colder months of the year.

• Complete guide to hedgehog hibernation

6. Tidy the pond before winter sets in

Most amphibians will have left ponds by October, so this is a good time of year to clear out dead plant material. Young froglets will be out and about and adult frogs are unlikely to have returned for winter, but sometimes you might find tadpoles or newt larvae in the pond ready to overwinter before developing into adults next year; so check carefully with a net first.

Rinse plant material in a bucket of pond water before you compost it to remove any aquatic animals and leave on the side of the pond overnight. Avoid cutting back plant material that hasn’t fallen into the water so it continues to provide as much cover as possible for wildlife over the winter months. Make sure any overhanging branches are pruned back to allow as much sunlight to reach the pond as possible.

7. Leave perennials to stand tall for winter wildlife

Wildlife-friendly gardening often relies more on what you don’t do in the garden than what you do. Leave as much vegetation standing overwinter to give invertebrates places to shelter in cold weather. I’ve found moth pupae attached to plant stems in the winter and ladybirds sheltering in seed heads. Birds will feed from a variety of seed heads if they are left standing over winter.

Leaving areas of long grass also provides a suitable habitat for small mammals, such as voles, to shelter and forage. Dead vegetation can then be cut back in spring just before the new growth appears.

8. Prune for next year's bumper raspberry harvest

If you haven’t yet pruned summer-fruiting raspberries like ‘Glen Ample’ and ‘Octavia’, prune them this month. Cut the old, woody stems that have fruited this year down to the base, but take care not to prune out any of the new shoots that will bear raspberries next year. Choose about six of these new stems and tie them into your framework.

Don’t prune autumn-fruiting raspberries yet, as many varieties should still be giving you a delicious harvest. Varieties like my favourites ‘All Gold’, ‘Autumn Bliss’ and ‘Joan J’ should be fruiting now and they’ll need pruning to the ground in late winter.

9. Make leaf mould

Collect leaves from deciduous trees and shrubs to make leaf mould. Store in mesh bins made of chicken wire and keep the leaves moist. If you don’t have room for leaf mould bins, you can still collect moist leaves in black bin bags with holes in the sides or we’ve successfully used biodegradable woven jute sacks. Shred larger leaves such as sycamore and horse chestnut to speed up decomposition before adding them to the sacks.

Leaf mould is a fantastic resource to add to homemade seed sowing and potting compost once it is well-rotted (over two years old). Any that is less than two years old can be used as a moisture-retentive mulch on flowerbeds. Leaf litter is an important natural habitat for wildlife, so it’s important not to collect it from woodland.

10. Multiply your favourite perennials

Autumn is a great time to divide your summer-flowering herbaceous perennials, once they’re no longer in active growth. Most perennials benefit from being divided every two to three years. Choose a dry day, when the soil can be worked with creating compaction, and water plants well afterwards. If autumn is exceedingly wet, leave division until the spring.

Plants that can be divided at this time of year include hostas, heucheras, hardy geraniums, crocosmia and astilbes. There’s something magical about creating new plants and either adding them to your own borders or giving them away to friends and neighbours.

11. Bring herbs indoors

For fresh herbs in late autumn and into winter, bring a few plants like chives, tarragon and mint indoors now and leave them on a sunny windowsill. If plants need to be lifted from the ground and transferred into pots, leave them outside for a couple of weeks to acclimatise to their new growing conditions before bringing them inside.

Mint can also be propagated indoors from short lengths of root. Young mint plants should begin to develop within a couple of weeks and you’ll be harvesting leaves in no time. Evergreen herbs like thyme and semi-evergreen herbs like winter savoury should continue to provide leaves from outdoor plants throughout the winter, although the taste isn’t generally as good as when harvested at other times of year.

12. Plant winter containers and protect pots

Before planting up winter displays, check that the containers are frost-proof and ready for cold weather. Group pots together over winter and raise terracotta containers up on pot feet to avoid waterlogging, which is more likely to cause pots to freeze and crack. Wrap containers with less hardy plants in recycled bubble wrap, straw or bury them in the ground with just the pot rim above ground. Alternatively, bring them into a frost-free place until after the last frosts in spring.

Plant up containers for winter with evergreen stalwarts such as miniature conifers, skimmia, Gaultheria mucronata and ornamental cabbage. These can be surrounded by colourful winter bedding, including Cyclamen persicum (which need to be in a sheltered spot in winter) and violas. My go-to combination outside my front door relies on the vivid red winter stems of Cornus alba ‘Sibirica’ with snowdrops, cyclamen and then primroses for early spring.

• Best winter plants for pots