Clearing the garden in autumn is a headache.

During the summer, nearly all garden rubbish is soft, wet and nitrogen-rich. In the autumn, however, fallen leaves, pine needles, rhododendron leaves, woody prunings and prickly rose stems are dry, slow to rot down and rich in carbon, so you need to deal with them differently.

Deciduous leaves are fairly easy - pile them into your home compost bin, where they will blend happily with weeds and kitchen scraps to produce good compost. It is even better to treat them separately by making a wonderful autumn harvest of leaf mould. You would be mad to throw out this perfect mulch, soil conditioner and potting mix.

Leaves break down quickly when exposed to winter rains so build a special leaf bay if you have lots of them (you will find instructions on my website). If your garden is small then soak the leaves and cram them into a bin bag, piercing holes in the sides. Leave the top open; otherwise it can be difficult getting the balance between air and moisture right. You will have good leafmould in 18 months. Builders' dumpy bags also work well.

Tannins in oak and beech slow decomposition to 30 months, but pine and spruce needles and the shiny, almost rubbery rhododendron, magnolia and holly leaves are much harder, taking several years to turn into compost or leafmould.

There are several reasons for this leisurely rot. Although deciduous leaves absorb water easily, the shiny coating on evergreens repels water and this slows down the composting process. Evergreens also use thick, tough leaves to protect themselves from attack by pathogens and herbivores. Whereas deciduous trees prevent a build-up of pests by discarding leaves every year, evergreens hang on to their leaves for several years. Insects find the thicker leaves much harder to break down and are repelled by the bitter toxins in the leaves.

Fortunately for us, research has shown these toxins do not survive the composting process, so it is perfectly safe to compost such leaves. And there is no risk that pine needles will cause acidic compost.

So how do you treat the slow rotters? You can reduce your wait by breaking up the leaves. This lets fungi and some water into the leaves to speed things along. Run a rotary mower over a pile of leaves, using the rotor blade as a shredder, or use a leaf vacuum to break them up.

However you treat waxy leaves, store them separately and leave for several years. Pine and spruce needles also make an excellent, natural, long-lasting mulch round trees and shrubs. They rot down slowly and are gradually incorporated into the soil.

Woody prunings also make a good mulch, when shredded. The wood contains very little moisture and the fungi that break down lignin in the wood need nitrogen for this. So you could bag up the shreddings and mix with nitrogen-rich grass clippings next year. This combination will make good mulching compost within a year.

You can safely put chopped up woody prunings in the compost heap, but first put aside any twigs that look strong enough to act as natural (and free) plant supports for next year. Get your stakes in early and your plants will grow in and through them beautifully.

I have just finished pruning my climbing roses. A dead hedge is the best place for all these prickles. Drive in two lines of stout poles, 45cm apart in rows 18ins to 2ft apart. The prickly stems will rot down over a few years in a dead hedge, making room for later additions. The hedge becomes a magnet for wildlife, attracting insects and feeding birds, not to mention toads and hedgehogs. You could also weave willow, cornus, ivy or clematis prunings between the posts to finish off with a basketwork effect.