Are your borders looking overgrown and overcrowded? If some of your stalwart shrubs and perennials have outgrown their space or simply aren't thriving in their current position, it may be time to move them.

The best time to transplant shrubs is while they are dormant, between late autumn and early spring. Choose a day when the ground isn't frozen or waterlogged.

There's always a risk when you move plants and the larger the plant, the more risk there is that you'll lose it. But there are ways to minimise that risk.

Small herbaceous perennials and compact shrubs are relatively easy to move if you water them thoroughly and then dig them up with as much root as possible, repositioning them somewhere where there's more room or where conditions are more favourable. Water them in well and keep them well watered during the autumn in the absence of rainfall.

Mature shrubs are harder work to move, but it's best to do it after a bout of rain. Get a friend to help you if the shrub is extremely large.

Generally those that move most easily are the ones with fibrous roots - masses of thin roots which remain shallow in the soil. More problematic to move are those with tap roots, which are much thicker and there are fewer of them. It's difficult to move these without breaking the roots.

First, decide where you are going to replant any large shrubs. Dig a hole slightly bigger than the root ball of soil is going to be and add organic matter to the soil as well as slow-release fertiliser.

For trauma-free transplanting of large shrubs, first make a wide circle at least 30cm from the shrub with a spade and dig a deep trench following the circle's curve. Use a garden fork to loosen the earth around the ball of the roots, then gently fork the surplus earth from around the roots.

If the stems or branches of the shrub are unwieldy, tie them loosely with garden string so they don't snap off or get damaged during the excavation.

Once the ball of roots has been loosened, dig your spade under the root ball as far as you can, levering gently as you go around the circle. The aim is to keep as large a root ball attached to the plant as possible.

When you feel the shrub move, tilt it to one side and slide a length of plastic sheeting or sacking underneath the root ball. Tilt the shrub the other way and manoeuvre the sacking so that it comes underneath the whole root ball, then wrap it up and tie it around the trunk securely, to minimise water loss and keep the root ball and soil intact.

Unwrap the sacking and carefully place the shrub in its original depth. There should be a distinct soil mark on the shrub, so it's easy to gauge. Fill the hole with displaced soil, firm in gently with the ball of your foot to get rid of any air pockets and give it a good soaking.Water regularly until the plant becomes established and mulch with organic matter. Large shrubs may need support for a year or two.

Some plants react better to being moved than others. Those which are easier to move include rhododendron and azalea, hydrangea, hebe, fuchsia, Choisya ternata and forsythia.

Peonies don't really like being relocated and it may take a couple of years before they flower again. Shrubs which don't like being transplanted include ceanothus, berberis, holly, eucalyptus, buddleia, cotoneaster, weigela and lilac. But even if they suffer leaf fall after moving, don't give up on them because they may come round.

BEST OF THE BUNCH - Plumbago

This frost-tender, scrambling or climbing evergreen shrub bears long-tubed flat flowers in dense clusters from summer to late autumn. The bright matt-green leaves provide the perfect foil for the sky-blue, pure white or deep rose-pink flowers and the plants look good for most of the year. In mild areas, grow plumbago over a pergola or arch, or against a wall. In cooler areas where temperatures fall below 7C (45F), they'll do better in a container in a sheltered, sunny spot and moved under cover in winter. Grow them in fertile, well-drained soil in full sun or in containers of loam-based potting compost, and top-dress or repot in spring. The most popular, P. auriculata, grows up to 6m (20ft), producing flower clusters up to 15cm (6in) across. Tie stems in to support as growth proceeds.

GOOD ENOUGH TO EAT - Storing vegetables

If you've had a good harvest, you'll probably be wondering where to store all your veg to ensure you've a good supply for the months ahead. If you're groaning under the weight of tomatoes, my best advice is to cook them into a passata or spaghetti sauce and freeze them in containers. French beans, sweetcorn, autumn cauliflowers and peas can be blanched and frozen. Harvested onions, garlic and shallots should be kept in a cool, bright, dry place to stop them sprouting. Some veg are best left in the ground until you need them, such as carrots and parsnips, although if you haven't used them by November, dig them up and store them in the salad drawer at the bottom of your fridge. Leave maincrop potatoes in the ground as long as possible, until frost is forecast. Lay them out in shallow trays to dry, then store them in thick paper or Hessian sacks in a cool, dark, frost-free place.

WHAT TO DO THIS WEEK

:: Sow sweet peas in pots and overwinter the plants in a cold frame to plant out next spring.

:: Continue to water outdoor crops such as tomatoes, beans and courgettes to encourage more fruits to ripen.

:: Continue blanching leeks, covering plants with tubes of cardboard or drainpipes.

:: Wrap trench varieties of celery with newspaper and draw earth up around the stems to blanch them ready for cutting in late autumn.

:: Cut down faded and dying flower stems from border perennials, tidying up plants.

:: Plant tubers of anemone 'De Caen' and 'Saint Brigid' at intervals, to extend their flowering next spring.

:: Plant evergreen shrubs or hedging plants while the soil is still warm enough to help them establish before winter.

:: Lift and divide congested clumps of perennials, replanting healthy segments of new growth into enriched soil.

:: Take hardwood cuttings from roses.

:: Continue pruning peaches to remove all shoots that have carried fruit, then tie in new shoots to replace them.

:: Where grass is thin, over-seed with a suitable grass seed mixture.

:: Make sure greenhouse heaters are in good working order.

:: Order new fruit trees and bushes to plant later this autumn and winter.