Coping with Weeds

By Libby Reeves

Every year when the temperature starts to increase and the sun shines on our damp winter soils, we wait in earnest for our lawns, borders and trees to flourish. But as the trees green and the borders start to flower, the weeds push up alongside them.

Weeds come in all shapes and sizes. Some have a big tap root, others seed everywhere, others spread via long tubes under the surface of the soil. The one thing they all have in common is that we want them to go! The methods to remove them are vast: spades, forks, hoes, bottles of potions, fancy tools that seem essential at the time of purchasing but then languish, unused, in the back of the potting shed for weeks…

So why do we actually worry about weeds? Apart from ruining the elegant landscape that we spend so long trying to perfect, weeds can actually be detrimental to our carefully tendered plants. They are often vigorous – a gentle herbaceous perennial surrounded by a clump of nettles stands little-to-no chance of survival as the nettles bulk up, taking space, light, water and nutrients away from the perennial plant. Allowing the weeds – particularly grasses – to grow around freshly planted trees and shrubs saps the moisture and nutrients away from the establishing roots, leading to a risk of poor growth and sometimes even tree death.

The density of plants in the garden when we allow the weeds to grow and establish can also cause a problem: the warm sheltered environment is a haven for fungi and insects that may delight in killing off our plants as they start to colonise our beds and borders. Vine weevil hide on the underside of dense vegetation during the day, before emerging at night to nibble the leaves. If allowed to reproduce, the grubs then bury underground and eat the dormant plant’s roots over winter, causing certain death of the many plants this pest can affect.

Some weeds are actually dangerous to our families and our pets: ragwort has a very pretty yellow flower yet will kill farm animals if ingested, and the pollen and dust on the plant is considered carcinogenic to humans. Giant hogweed has a sap that causes the skin to blister and burn so severely that gardeners clearing this plant have sometimes had to be hospitalised. Hemlock water dropwort is one of the most poisonous plants we have growing naturally in the UK, and ingesting a small amount is usually fatal both to animals and humans alike. Thankfully, it is not common in gardens.

So how do we remove these plants of destruction? The first step in weed removal is identifying the weed and learning how it grows. Annual weeds, or weeds that only last a short period of time, tend to have very small root systems. If you were to pull their heads off, there is usually not enough energy in the root to regrow. Hairy bittercress is a good example: removing the leaves of the plant will stop it growing, but be warned that if you miss even one silique, the seeds will fly out and last for years in the soil, spreading exponentially all over the garden. I suggest using a hoe to quickly remove as much of the plant as possible. A rake-up will then banish these weeds to the compost heap.

Ragwort poses a threat to animals

Weeds with taproots are notorious for being difficult to remove. These long roots, stretching down far into the soil, are full of sugar and can regrow from a small stump. Dandelions and docks are particularly famous for this. The ideal method of treatment here is a good sharp spade, running down next to the root and removing as much as possible. Although a tiny tip can still regrow, by removing most of the root, the idea is that the plant will expend most of its energy trying to reach the soil surface and so when the plant reappears, a second hit with the spade should be enough to kill the plant for good.

The plants with roots that spread underground, causing regrowth across the garden, are probably the hardest to cope with. Ground elder and bindweed are very common in the UK and will grow around the established roots of the shrubs and trees we love, causing complete eradication to be almost impossible. Ground elder will hand weed from the soil relatively easily with time and patience, but bindweed grows so deep that hand weeding can often make the problem worse. Success has been known by allowing it to grow up bamboo canes before cutting it off at the base, weakening the root system, and covering with a weed suppressing layer or matting will also help.

So why not run to the chemicals? There are many brands available, often advertised on the television, assuring you that their special blend will kill all your weeds from the ground up, never to be worried about again. The problem is that many of these chemicals may also harm the local wildlife, your dog, your family and all the other plants in your garden if not used correctly. On a professional level, to use these chemicals to the best effect, full body protection is required as well as rigorous training with exam-style assessments to ensure a user is competent. By the time these chemicals are made to a level the general public can use, they are heavily diluted, resulting in some plants developing resistance to the poisons. This is particularly impactful when weeds cannot be eradicated on farms and in orchards, where the success of the crops is vital for the growers’ livelihoods and ability to feed the nation.

It’s worth considering alternatives to chemicals before using them as a last resort. Ask yourself beforehand: is there a particular plant that requires chemical treatment? Have you tried digging it up first? The love of our gardens should also include the love of the soil and chemicals can leave trace elements that are damaging to the soil microorganisms too. Hand weeding can be so therapeutic, and the feeling of accomplishment when looking back on a freshly weeded border can bring as much joy as the sight of a flowering rose or the ambers of an autumn acer.

Whilst we don’t want weeds popping up in our growing areas, there are occasionally times where we can use them to our benefit. I will look at this in next week’s blog and discuss some ways that we can incorporate weeds into our garden.