How to control weeds

Weeds need to be controlled in the garden because they rob other plants of moisture and nutrient, make the flower border or veg plot untidy, and some harbour diseases like rust which can be passed on to garden plants. Dealing with weeds isn’t always easy, but follow the guidelines below.

  • Annual weeds like groundsel and chickweed are best controlled by digging or pulling them out before they set seed. On the veg plot weekly hoeing between the rows of vegetables will keep them under control and kill them whilst they are small.
  • Perennial weeds like ground elder, bindweed and horsetail persist from year to year and can develop extensive root systems. They’re difficult to dig out because even a tiny fragment of root can regenerate and become a large plant in the space of a season. Digging out weeds should gradually weaken them over time, but chemical control is the only sure option.
  • To get rid of perennial weeds, use a systemic (sometimes called a translocated) weedkiller which carries the chemical right down to the roots to kill the plant completely. Tumbleweed, Roundup and Weedol are examples of systemic weedkillers. They are inactivated on contact with the soil, and leave no residue.
  • Spray individual weeds, taking care that spray doesn’t drift onto nearby plants. Where perennial weeds are entangled with border plants, cover the plant with a plastic bag, making a hole for the weed leaves to poke through. Always use gloves when handling chemicals, and never spray on breezy days when it’s impossible to control the drift of the spray.
  • The best time to apply a systemic weedkiller is in autumn when the plants are drawing their resources back into their roots, but plants can be sprayed at any time from spring to autumn.
  • Some very difficult perennial weeds like bindweed and horsetail will take several applications to kill them completely. Both have very extensive root systems, and re-applying the chemical each time the leaves grow back will probably be necessary. Horsetail has smooth stems which makes it difficult for the weedkiller to adhere to. Trampling the stems to bruise and break them will help the chemical penetrate the stems – and make you feel better too!
  • When clearing badly overgrown sites, cut all the vegetation back with a brushcutter or strimmer and spray only after new foliage appears. You may want to rotavate the site before spraying; this will chop perennial weed roots into smaller pieces, but will give you a clearer site to work with.
  • In lawns, spot-treat perennial weeds as they appear, rather than spraying the whole lawn. The latter is not only expensive and wasteful, but is very damaging to the environment.

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