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Weeds and what to do about them in winter

by Emma Cooper

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Ragwort. Credit: Steve Slater

The war against weeds isn’t one that can be won, but now that winter is here there’s plenty that you can do to avoid having major problems – or spending hours weeding – next year. 

As the weather gets colder, most weeds die back, or at least slow down, for the winter. And as the plants in the borders are doing the same thing, it’s easier to see – and get to – weeds that have been hiding from you all summer. If you’re planning on replanting your beds, or putting in new ones, then it really is worthwhile dealing with the weeds now, to save time later.

Annual weeds – the big cover up

In weed control terms, there are only two kinds of weeds. Annual weeds are ones that grow from seed, flower and then set seed, all in one season. They’ll be the ones dying back for the winter, but in the meantime they may already have left their legacy of seeds in the soil. There’s some truth in old adage that “one year’s seeding means seven years weeding”, as many weeds have seeds that can lie dormant in the soil for many years. Digging over the soil brings them up into the light, where they will germinate in spring.

Annual weeds you may find in your garden include fat hen,groundsel, hairy bittercress and chickweed.

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The long-term solution to the annual weeds problem is to keep the soil surface covered with a layer of mulch, which stops light reaching the soil and encouraging weed seeds to germinate. A mulch can be anything from grass cuttings right through to a decorative layer of coloured gravel. Organic mulches like grass or bark chips are cheap and add nutrients to the soil, but they do need topping up on a regular basis so that they remain good weed barriers. Inorganic mulches like pebbles are more expensive, but you may find them more attractive and they last indefinitely. There are plenty of choices for mulches, so you’re bound to find one that’s right for you.

You might also like to try out living mulches – for example planting groundcover plants. There are many to choose from, all low-growing and happy to live underneath taller plants. When selecting which one(s) to plant you need to take into account the growing conditions – some like more light, some are happy in shade; some like damp soil and others prefer drier ground. Groundcover plants are a great choice for slopes that are difficult to weed and too steep to hold a mulch.

Another living mulch is green manure – although this is a shorter-term option. This is sown on bare soil which it can cover for a few weeks, several months or even years, depending on which variety you choose. It is very good for reducing weed problems on ground you want to use for something else soon. When you’re ready, you just dig in the leafy top growth, which feeds the soil (or you can cut it down and cart if off to the compost heap).

For applying mulches check out http://www.cityplanter.co.uk/practical/how-to/how-to-mulch

 When annual weeds do appear ideally they should be pulled up by hand before they set seed.

Perennial problems

Perennial weeds are the other type of weed. They are plants that live for several years, and they don’t need to rush to complete their lifecycle over the summer. They can spend time and resources putting down roots and building up food stores.

Common perennial weeds to look out for include bindweed, couch grass, horsetail, stinging nettle, creeping buttercup and ragwort.

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A mere mulch isn’t going to stop these hardened types rampaging through the garden, although if you lay down weed control fabric it should improve the situation – after two or three years. This would be a particularly useful solution for borders, where you can cover the fabric in a more attractive mulch layer, and avoid the need to weed in and around established shrubs.

If you have or have inherited a weed-infested garden then you could consider laying down weed control fabric and building raised beds on top – this will start you off with weed-free beds to grow your plants, and the fabric will take care of future weed problems too.

When perennial weeds do appear they really need to be dug out, and how difficult a task that will be depends on the weeds. Brambles for example can form quite big clumps of roots, but if you get most of them out then that’s usually good enough. Bindweed on the other hand grows long trails of brittle, white roots, and any tiny pieces that get left behind in the soil can grow into a new plant. Sifting the soil is one option to remove every shred of root, but it’s a long and laborious job. Indeed, most perennial weeds have extensive root systems and you need to make sure you have removed even the tiniest pieces.

Basically, to minimise perennial weed problems you need a combination approach – pulling up any fresh growth as you see it, digging out everything you can and then mulching the soil. With this kind of campaign eventually – hopefully – the weeds will starve to death.

The joys of spring

If you’ve dealt with the perennial weeds, and mulched over any bare soil, then you shouldn’t have too many weed problems in spring. It pays to keep on top of any weeds that do appear, either using a sharp hoe to slice off the top growth, or pulling them up whole and sending them off for municipal composting. (You can safely add annual weeds to your compost heap, as long as they’re not flowering or full of seeds. Perennial weeds might regrow, and are best sent elsewhere.)

When you’ve spent a lot of time and effort (and possibly money) dealing with your weed problems, then it can be annoying to see the fresh flushes come up in spring. But try to think positively – for one thing, their appearance means that the weather is warming up, and the gardening season is on its way. With your weed problems under control you can concentrate on the fun parts, planting and enjoying your garden.

And you could re-visit the thinking of the past when emerging weeds were valued as spring greens -eagerly awaited and considered as a tonic supplying as they did some much-needed vitamins after a long winter. Get yourself a copy of Food for Free by Richard Mabey, and start looking at your weeds in a different light. After all, most people find weeding a chore. But harvesting free vegetables for dinner? That’s a different story.

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