Our shopping list at the garden centre will be much longer than usual this weekend, as we contemplate all the dead wizened stumps of our ‘hardy’ herbs and shrubs. And these are hard to compost.

Home composting does change garden waste into a fertile garden resource so we don’t want to throw anything away. But too much dry, brown, woody waste causes problems.

Normally, it’s mixed with green, sappy grass clippings, weeds and raw kitchen scraps. They moisten and soften dry waste so it’s easier for microorganisms to break it down into compost.

Ideally, use a garden fork to mix everything in the top 30 or so centimetres of the composter. Too much green, like lots of grass clippings, makes a dense, airless, smelly heap, and nothing happens to a pile of brown waste.

Look around and you’ll see what I mean. A branch or stump on the surface of the ground can take many years to rot away, but bury it and the moist soil and busy bacteria and other micro organisms will greatly speed up the process.

Branches, stems and twigs firstly need fungi for decomposition. And resins in conifers and many herbs are a challenge only fungi can handle. Only after this will microscopic organisms get to work.

So what can poor gardeners do with all this dry stuff?

As with all compostable material, the smaller it is the faster it breaks down. Soil creatures, like worms, work round the moist perimeter of plant debris: woodchip is faster than a branch just as chopped up cabbage leaves disappear more quickly than a thick sprout stem.

Shredding undoubtedly speeds up decomposition in a compost bin and this especially applies to woody stems. So you can easily add the shreddings of herbs and thin stemmed shrubs to a compost bin, but they will take a bit longer to completely rot down.

Thick, woody branches would take much longer even after shredding: 2 or 3 years for ash and birch, 5-7 for many other trees, especially conifers. Instead of composting, use the shreddings to make good paths or as mulch round shrubs and hedges.

Do the same with sawdust, wood shavings and wood bark. Other slow rotters are rabbit and guinea pig bedding. If you have enough room, set up a separate composting unit for these.

The resulting compost will contain some nutrients but is best used for mulching, gradually rotting down and adding structure to the soil.

The larger the garden, the more space you have for these extra methods to deal with woody waste.

And there are prunings, such as rose, that you wouldn’t shred: imagine walking or kneeling on rose, holly or gooseberry shreddings.

The solution is a dead hedge for that lot and branches too large for a shredder.

Choose a discreet corner, perhaps a shady space you can’t use for anything else. It could be up against a wall. Corral the waste by driving in poles to define the area.

You could even make it more attractive by weaving in some of the pliable waste, willow, clematis or ivy to make a small retaining wall.

Gradually fill up as material comes available and see it very slowly rot down over several years.

The dead hedge becomes a vibrant spot, almost as attractive to wildlife as a compost heap. Insects, amphibians and even hedgehogs will shelter and birds will treat it as a restaurant or nest site.

Who knows it might become a garden feature? Many visitors to our public composting demonstration were inspired to copy the idea.

As a last resort, use the green waste, not the landfill bin for what you can’t manage.

Plant of the week

CRAB APPLE BLOSSOM. All crab apple cultivars of Malus sylvestnis have showy, sweet-scented

blossom in spring that is very attractive to bees. Delicate pink and white blossom set off by a blue spring sky is delightful.