A war on weeds
With some weeds producing thousands of seeds per plant, it’s hard work to get rid of them. Try managing them instead
Keep weeds in check with an oscillating hoe, favourite of many professional gardeners. Photograph: Richard Johnston
What a month it’s been for weeds. I seem to have spent the past few weeks with a hoe in one hand, a daisy-grubber in the other and a heavily-laden wheelbarrow by my side into which I’m forever flinging dripping heaps of creeping buttercup, dock, ground elder, hairy bittercress, and a host of other uninvited guests, all of which arrived by stealth. Some – dandelion, thistle, willow and willow herb – parachuted in, each tiny silver-haired seed carried aloft from nearby damp meadowlands on a summer breeze.
Others were dropped in, the seed mixed inside the excreta of visiting birds. A few, including hairy bittercress, were flung in by ripe seedpods that exploded at the lightest touch.
Others – ground elder, creeping buttercup, bindweed, scutch grass, coltsfoot, horsetail – crept in via the tentacle-like stolons or rhizomes of the parent plant. If not that then they were brought in accidentally either as seed or spores or root fragments concealed inside a trailer-load of manure, or in imported topsoil, or in the rootball of a plant. The thing about all of these weeds, whether ephemeral, annual, biennial or perennial, is that once they’re in the garden they are terribly difficult to get rid of.
Just one creeping buttercup plant can produce almost 700 seeds, a single shepherd’s purse plant will produce an average of 4,500 seeds, while chickweed is capable of producing up to 25,000 seeds per plant– even, astonishingly, when under a blanket of snow. Some of those will quickly germinate but the rest remain dormant in the soil as part of a garden’s natural seedbank, patiently waiting for the right growing conditions to trigger germination. Which means that trying to entirely eradicate weeds from a garden or an allotment is a task as futile and exhausting as it is tedious.
That aside, weeds serve many useful purposes, whether culinary, medicinal or as an important food source for garden wildlife. They can also be an indicator of a soil’s fertility, its pH, even its temperature. As soon as I see that first rash of weed seedlings in spring, for example, I know that conditions are right to begin sowing.
Many, including the common nettle, can even be used to make a nutrient-rich liquid plant feed, or their leaves added to the compost heap (nettle, dandelion, coltsfoot) to speed up the rate of decomposition and add important plant nutrients.
So rather than trying to get rid of them entirely the aim should be to manage the weeds in your garden. This means preventing them from overtaking flower borders or vegetable beds where they’ll compete with plants for light, space and nutrients, offer leafy cover for slugs and snails, increase the risk of certain plant diseases and pests, and reduce yields. The best approach here is a multi-pronged one.
My first piece of advice: where possible avoid digging as it brings many thousands more weed seeds to the surface.
The second is to invest in a good quality hoe. Hoeing is far faster and much kinder to the back and knees than hand-weeding, its only drawback being the fact that it’s less effective during wet weather. Used properly and regularly from early spring, it will reduce the need for hand-weeding by as much as 90 per cent and will gradually deplete your garden’s weed seedbank. It also radically reduces slug populations by exposing slug eggs to hungry birds.
Inevitably there are tight spots in a garden that have to be weeded by hand. Invest in a pair of Showa Floreo gardening gloves, which keep hands dry, warm and protected from nettle stings but are still flexible and lightweight enough not to impede progress. Also invest in a few good hand tools such as a daisy-grubber, or Dutch firm Sneeboer’s digging fork or spade.
Remember also that weeds with very persistent root systems or those that have already formed seed-heads should be kept out of the compost bin unless you keep a very hot heap. One alternative is to nip out and bin any seedheads, then chop up and bag the rest of the plant, which will eventually transform itself into rich dark compost. Frustratingly, there are times when even diligent hoeing and hand-weeding won’t be enough to rid a bed of especially persistent perennial weeds such as bindweed or Japanese knotweed, both plants whose root systems go far into the ground. In this case your options are limited. The organically-friendly approach is to dig out as much of the roots as you can and then treat the bed as a temporary lawn, mowing/strimming regularly to gradually weaken the weeds’ root systems. This will take a couple of years to be properly effective. Other gardeners might be tempted to take the quicker but organically unfriendly approach and target-spray the offending weeds with Round-Up.
Weed-suppressing mulches are another useful way to prevent weed seeds in the soil from germinating. These might be of garden compost, manure (cover manure heaps with plastic to keep them weed-free), straw, seaweed, leaf mould, cocoa shell, even a layer of dampened newspaper or cardboard. To be effective it must be at least 2.5cm thick and left undisturbed.
Another trick is to temporarily cover the ground with black polythene or to grow a green manure. Planting densely and using low-growing ground cover plants will also help, while weed-suppressant fabrics such as mypex are another useful tool.
Combine at least some of these techniques and you’ll have a garden where weeds will know their place.