Weeds to leave alone – at least for a time

No-one is advocating a garden full of weeds but you may be surprised to know that some help build up vital minerals in the soil that will be good for the plants you grow there later

If you are an extremely tidy gardener, don’t read this. Turn the page instead – you may disagree with the next statement. We need some weeds in our gardens.

Weeds are commonly described as plants in the wrong place, and many of them are just native wild flowers. There are some, mainly from introduced plants such as Japanese knotweed that have proliferated in some areas and have caused major environmental problems so that they are now regarded as an infestation, with expensive programmes in place to eradicate the problem.

But there are others that we should encourage, as they will bring diversity and increase the wildlife we see in our garden. Some, like nettles, will attract butterflies, and others such as poppies may be the remnant of the original local flora and so help keep up the numbers in insects and wildlife generally.

They may be part of a valuable but complex eco-system that keeps the rest of the garden free of pests.

If we are too tidy, we can create an arid plot, doing nothing for the natural world around us. Weeds fix and stabilise the soil, and can act as protectors for emerging seedlings. It’s all about getting the balance right so that the weeds don’t take over.

At some point you will need to weed a flower bed or vegetable plot. Organic gardening guru Bob Flowerdew says it’s all about getting the timing right, so that you have the benefit of the fertility they create, before they get out of hand.

He also says that you need to know your weeds to get this timing right. Weeds provide green manure for soil when no crops are there – that’s why many gardeners grow grasses and crops such as wild mustard from seed on their vegetable plot and in their raised beds in autumn, to dig up in the spring before planting the season’s crops.

Some weeds build up vital minerals in the soil that will be good for the plants you grow there later. Clovers and vetches fix nitrogen, while comfrey accumulates potassium, as do nettles and thistles.

Flowerdew says that the more growth the weeds make the more material you will have for the compost heap – and that a bed of nettles when dug up will give fertility to the heap for a couple of years. But leave a corner of them for caterpillars to feed on, so that you have plenty of butterflies later.

No-one is advocating a garden full of weeds. Annual weeds can be dealt with by hand weeding, hoeing, laying old carpet over them, a mulch of bark clippings or even newspaper and then a layer of grass clippings. Perennial weeds do need controlling, bindweed and ground elder among them. Try to find any roots which could make new plants. Dunk bindweed and ground elder roots in a bucket of water for a few weeks, or let them dry up on a path, then bin them.

If you see some wild violets or gladiolus, poppies or field scabius, even Queen Anne’s Lace (Daucus carota) among your flowers, or even among your vegetables, be thankful that beautiful wild flowers seek your garden as a haven now that so much farmland is harmful to them.

Beneficial weeds for the garden - in moderation

• nettles – add fertility to soil (then compost heap), good for caterpillars
• clover – adds nitrogen to the soil; use as green manure, dig up in spring
• comfrey
• wild mustard
• wild vetch
• chickweed – can be added to salads
• shepherd's purse – edible, can be sauted
• wild grasses – over-winter, dig up in spring