Waltons ultimate guide to weeds
Keeping weeds under control in your garden is important because they compete with your favourite plants for sunlight, water and nutrients.
It’s a good idea to remove them, but first you need to identify the most common culprits and understand how they spread. You may decide to allow some ‘weeds’ to remain, at least for short periods, as they attract wildlife and pollinators. Other weeds are so invasive that it’s best to get rid of them as quickly as possible. We’ve put together this list of common garden weeds to help you identify and control them effectively.
What is a weed?
The broad definition of a weed is ‘any plant growing in the wrong place’. But this covers hundreds of different plants and it can be difficult to work out which are weeds, and which aren’t. Weeds can be perennials or annuals, but generally, they fall into three main types:
- Grassy - any unwanted plant that appears in a lawn. Similar in appearance to grass, they can be difficult to identify.
- Broadleaf - a nuisance variety that’s easy to identify and treat without harming surrounding plants.
- Wood and vining - often invasive, these creeping plants can look very attractive and are sometimes grown deliberately. Some are known to kill other plants and others can irritate the skin when handled without gloves.
No matter what weed you’re dealing with, the main rule is to kill the root by completely removing it. If you only remove the plant from above soil level, it’s very likely to come back.
Also known as Hedge Bindweed or Bellbind, this perennial climber has thin vines that wrap tightly around plants and other structures. The vines eventually grow arrow-head shaped leaves and in summer it produces white trumpet-shaped flowers. It quickly smothers hedges and shrubs if left unchecked.
Bindweed has a hardy root system and it can take several attempts to remove it. A chemical control method is most successful. Spray a systemic weed killer on the leaves (i.e. a chemical that’s absorbed into the plant and attacks from the inside). Apply in the early evening during the flowering period for the best results.
In densely planted beds, push canes into the ground and encourage the bindweed to grow up them and away from more precious shrubs. This makes the leaves easier to spray or paint with a chemical gel.
A common perennial weed, the dandelion is a member of the sunflower family that forms a large, flat rosette and grows in lawns, patios, paths and borders. The leaves are long with a jagged edge, like lion’s teeth, which is how the plant got its name. Hollow stems rise from the centre of the plant to support vibrant yellow flowers. These are followed by the distinctive fluffy spheres of seeds that children love to blow into the air.
Happy in sunny or shady conditions, it can easily take over a garden. The best form of control is to carefully tease up the dandelion’s long tap root with a fork to avoid breakage. If any part of the root is left in the soil, it will produce several new dandelion plants. Young plants are much easier to remove. If the dandelion is growing in a path or other hard-to-reach area, paint the leaves with a systemic weed killer or use a flame or heat weed gun. You may need to repeat these topgrowth treatments several times to completely eradicate the weed.
That all said, dandelions are an edible plant and and a good early source of nectar for bees. Some gardeners are happy to sacrifice a perfect lawn to help pollinators, but it’s a good idea to remove the flowers before they produce seed.
The distinctive white and yellow daisy flower is one of the most common and recognisable lawn and turf weeds in gardens in the UK. Spoon-shaped leaves form a rosette from which a cluster of flowers emerge.
Daisies can grow in almost any soil conditions and spread by short runners called stolons. A perennial weed, they last for several years. The daisy’s leaves grow very close to the ground meaning that it can survive in close mown lawns.
To remove daisies, dig them out with an old kitchen knife or spiked “grubber” tool and a good quality kneeling pad to protect your knees! Alternatively, apply a systemic weedkiller to the leaves or use a specialist lawn weed and feed product that won’t harm the surrounding grass.
Nettles are common garden weeds most of us can easily identify because of their jagged leaves. There are annual and perennial varieties, both of which have tooth-edged leaves covered with stinging hairs. They bear greeny-brown tassel-like flowers during the warmer months and can quickly take over large areas of a garden or vegetable plot.
They spread by seed and have creeping roots. The best way to control individual clumps is by digging them up before they seed (by mid-summer). Take care to remove any creeping stems, as any piece with a node can produce a new plant.
For clearing large areas of nettles, spray with a weedkiller when the plants are in vigorous growth just before flowering - June is about the right time of year. You may need to repeat the process again in September.
Frequently tilled soil is less likely to attract nettles and the tilling is a good way to prevent their return. However some wildlife gardeners choose to deliberately leave a ‘managed’ patch of nettles in a corner of their garden for butterflies and other pollinators.
Dock is common in most gardens, and many of us use it as a treatment for painful nettle stings. It usually grows on lawns but can pop up almost anywhere. There are two varieties - broad-leaved dock with long-stalked, smooth oblong leaves; and curled dock with tapering, wavy-edged leaves.
Dock can be difficult to get rid of. It has a deep, forked tap root from which it can regrow, and and it also produces large amounts of seed.
To control dock, dig it out in the spring when it’s most vulnerable. Remove at least 20cm of the root stock to be sure the plant will not be able to regenerate. For established dock, a glyphosate weedkiller is the most effective treatment. Use a gel formula to target individual weeds and prevent harm to surrounding plants. Mid-summer is the best time to attack.
This aggressive, perennial weed spreads by deep roots and air-borne seeds. It forms large clumps of spiny leaves and produces tall stems of lilac flowers in the summer.
Once established, creeping thistle is difficult to get rid of. It is possible to dig it out, but as it regenerates from broken roots you may need to do this over two to three seasons before you completely eradicate it.
Chemical control is the best solution for this weed. Spray with a systemic weedkiller containing glyphosate, or spot-treat leaves with a gel just before the lilac flowers begin to show.
Creeping Buttercup is a low growing perennial weed that forms mats. It prefers wet heavy soils, but grows nearly everywhere in the garden. The plants are easily recognisable by their three-lobed serrated leaves and bright yellow, glossy flowers.
Common in lawns, it spreads using creeping stems that run along the surface of the ground, extending upwards into a new plant at regular intervals. The roots are fibrous and dense, making it difficult to remove permanently. It can take several years to get rid of.
If you catch it early you can control creeping buttercup by removing it by hand with a small fork. Be sure to get all the roots to prevent re-growth. For a chemical solution suitable for grassy areas, use a selective herbicide lawn weedkiller that will target the weeds without harming your lawn. In beds and borders carefully spray a systemic weed killer containing glyphosate, or use a paint-on gel formula on the foliage.
Horsetail is a deep-rooted perennial weed that spreads quickly through beds, borders, patios and lawns. Light brown stems with a small cone on the end give way to green, fir-tree like plants in summer that can reach up to 60cm tall.
Horsetail spreads via creeping underground stems called rhizomes, often from neighbours’ gardens or brought in with manure. Sometimes with roots established several metres deep, they are very difficult to dig out and that can, in fact, make the problem worse as the plant re-grows rapidly from pieces left behind.
The best form of control is a tough weedkiller containing glyphosate or a paint-on gel. Attack in late summer after bruising the shoots with a rake. It may take several seasons to completely conquer this weed.
When it comes to keeping your garden weed free, prevention is better than cure. Learn to identify weeds early and you’ll keep one step ahead of the game. Weeding is an ongoing task for any gardener. Little and often can greatly limit the amount of chemicals you need to use to keep unwanted plants under control. If you do resort to chemical solutions, read the instructions carefully before use, especially if using near fruit and vegetables destined for your table.
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