Hedgehog populations are in trouble. They've declined by 30% in the last 10 years alone and there are now thought to be fewer than a million left in the UK, according to the RHS.

So, what can gardeners do about it? This year, the RHS and The Wildlife Trusts are teaming up with the campaign Hedgehog Street during Wild About Gardens Week to encourage us to make gardens, schools and community spaces hedgehog-friendly.

"Improving your gardens for invertebrate groups will encourage hedgehogs into the garden, as insects, slugs, snails and earthworms are the hedgehog's natural food source," says Helen Bostock, RHS senior horticultural adviser.

Hedgehogs are not herbivores, so will not feast on leaves, flowers or other plant matter, but they will feed on the pollinating insects and other species which are attracted to particular plants.

As well as feeding on slugs and snails, hedgehogs also eat groups of beetles, caterpillars, earthworms and even birds' eggs, as well as meat-based dog and cat food, or dry hedgehog food available from garden centres and online.

"There's going to be an indirect benefit when it comes to plant choice," says Bostock. "If you increase invertebrates you will encourage the hedgehogs' natural food sources."

At this time of year, just before hibernation, good pollinating plants including asters, dahlias, Japanese anemones, sedums and Verbena bonariensis will all encourage just the type of invertebrates hedgehogs need to get them through the winter.

At other times of the year, a mix of flower shapes will attract a variety of insects, from tall foxgloves, to climbing honeysuckles, ornamental alliums, salvias, single flowered roses and herbs, including rosemary and chives.

Bear in mind that hedgehogs only have short legs and don't do well on steep inclines, she says.

"Remove potential hazards. Any steep sides on ponds can lead to hedgehogs drowning. Create a gentle ramp to allow them easy access in and out of the water.

"Check bonfire piles before you light them, as hedgehogs may be hiding underneath them and be careful when strimming long grass, where they may be found. Also, don't leave litter or items like fruit cage netting loose for hedgehogs to get caught up in. Open drains and trenches can also cause problems."

Wild About Gardens Week will also be encouraging people to create 13cm x 13cm hedgehog holes in fences, walls and other barriers to allow these creatures to access different gardens for food and shelter.

"Solid boundaries are problematic for hedgehogs," says Bostock. "Adults travel between 1-2km per night and need that space to forage."

Gardeners should not cut everything back as soon as late autumn arrives, she says. Leave some stems standing to provide effective cover and if you want to buy or make hedgehog shelters, make sure they are sturdy and that their holes are big enough for access, and place them in a quiet spot with natural cover such as leaves, so that rain doesn't flood the shelter.

To illustrate the point, RHS Harlow Carr in Yorkshire is launching three gardens which are each 5m x 5m - one contemporary, one formal and the other wild - with small holes in the boundaries to allow hedgehog access, featuring planting which will attract invertebrates and hedgehog shelters.

Leafy plants including hostas, which provide both cover and attract slugs and snails, which are food for hedgehogs, are featured in the gardens, as are willow shelters, short grasses and bare soil, where they can forage for worms.

:: Wild About Gardens Week runs from October 26 to November 1. For details go to www.wildaboutgardensweek.org.uk/events

BEST OF THE BUNCH - Liriope

This underrated perennial provides a dense evergreen clump of strap-shaped leaves all year round, but its moment of glory comes in autumn when striking violet flowers appear. They combine well with bright pink Nerine bowdenii or colchicums, or alternatively establish clumps between spring-flowering shrubs, where their leaves will add year-round interest. Liriope muscari, a reliable tough plant, prefers neutral to acid soil and can withstand drought, seaside winds and shade. However, they do flower best in sun. Many have variegated foliage. White-flowered types include 'Monroe White', which grows to 25cm (10in). In spring, cut down old leaves to the ground to encourage fresh new growth.

GOOD ENOUGH TO EAT - Shallots

Shallots are often seen as the up-market relative of onions, having a milder flavour and looking and tasting delicious whole in casseroles, as well as being perfect for pickling. Yet they are as easy to grow as regular onions. You buy sets in February and March, planting them out with a trowel so they are just covered by soil, spacing them 20cm (8in) apart in rows 30cm (12in) apart. The area needs to be kept weed-free and you'll need to water them in periods of dry weather. Havest them when the leaves turn yellow in July or August, lift and then dry them in the sun, spreading them in layers in a frostproof shed. Good varieties include 'Griselle' and 'Golden Gourmet'.

WHAT TO DO THIS WEEK

:: Cut seedheads of Acanthus spinosus, teasel and globe artichokes to dry and use for decoration in the home in winter

:: Lift, divide and replant older clumps of perennials such as crocosmia, hardy geraniums and hostas

:: Lift canna lilies, which can be treated as tender perennials, trimmed and potted into peat-free compost, stored in a frost-free place where it's cool and dry

:: Continue to plant spring-flowering bulbs

:: Pot up half-hardy fuchsias and take them under cover if necessary, keeping them cool and dry but don't let them dry out completely

:: Begin winter digging once the ground has been cleared, particularly if you have heavy clay soil, which benefits from being broken up and exposed to winter weather

:: Pick the last of the runner beans and, if they are not too large, freeze them

:: Cover bare ground with polythene to protect the soil from winter rain

:: Remove old yellowing leaves on Brussels sprouts and other winter brassicas as they develop

:: Prepare the ground for new fruit trees, digging over the area and incorporating plenty of organic matter