Well, that's it then, right? Summer is as good as over. No more gin-and-tonics on the garden wall or dinners under the plum tree. No more garden tourists till next spring, either, and just as well. The annuals look leafy and leggy, the slug and earwig damage is starting to show, and even the tireless bellflowers are down to their last buds. Time to slip into the duck shoes, haul out the big tools and get to some serious work.

Despite what others may think, fall is a grand time for gardeners, with no one looking while we reappraise the season past, harvest our triumphs, compost our defeats and surreptitiously prepare next summer's delights.

There is, for instance, no better time for transplanting – or planting, come to that. The only problem with putting in new things now is that garden centres don't want to be stuck with inventory for the winter, so they don't stock nearly the range of plants they have in spring. If you can find what you want, though, or only want to move things you've got, now is the time. Most trees, shrubs and perennials have stopped producing leaves and flowers and are just entering a period of vigorous root growth. They won't resent new digs to dig into, and may well welcome the notion – especially if there's some fresh topsoil or compost (though not fertilizer) involved.

Plants moved now (or planted new) will have up to two months to settle in and spread their roots before they go dormant. Plus another roughly two months' jump on next year's April transplants, because their roots will start growing again as early as February. The size of a perennial's root system pretty much dictates its size aboveground, so the plant you put in next April will not, for at least a season, much overshadow an area the size of the pot it came in. But put the same plant in the ground now and the diameter of its roots – and consequently next year's plant – could double that.

The flip side is, of course, that any perennial weeds left in the garden now will also have the same weeks of root growth to get bigger and stronger for next spring, so it's in your own interest, no matter how thankless the task may seem, to also now get the garden as weed-free as you can, starting with the weeds at the edge of the bed – the ones you've been fertilizing all year.

Right now, you should dig an air trench – a V-shaped cut that most gardeners use to keep grasses (or groundcovers, or near-the-surface roots of trees and shrubs) out of garden soil. Briefly, with a sharp, square-ended spade, slice into your lawn about two centimetres back from the edge of the garden, shoving the blade in deep, then leaning back on the handle to free a thin slice of grassy soil. Leave the slice in place, but reinsert the spade next to it to extend the cut. When you've gone a few metres, or the whole way along the edge of the bed, return to where you started and gently lift the soil slice away -- or as much of it as contains roots -- taking out any stolons or rhizomes reaching into the bed, too, as you go.

That's the first and most important weeding task, but clean out as many other invaders as you can, too. Beyond that, I'd take it easy. I'm not one for cutting back all perennials after they fade, even in November, when other chores are done. I do rake up fallen rose leaves – and don't compost them – because of the risk of infection. And I cut hostas back as they wither rather than provide shelter for slugs. But a lot of finished perennials look handsome in the snow -- ornamental grasses, especially, but also taller sedums, such as 'Autumn Joy,' and some asters. Except for weeds, the cleaning up I do between my plants now is mainly to make room for bulbs.