The RHS believes that avoiding pests, diseases and weeds by good practice in cultivation methods, cultivar selection, garden hygiene and encouraging or introducing natural enemies, should be the first line of control. If chemical controls are used, they should be used only in a minimal and highly targeted manner.
The best time to apply weedkillers to nettles is when they are in vigorous growth, but have not yet flowered. Digging up the plants can be done at any time of year.
- It is important to prevent stinging nettles, especially the annual nettles, seeding by cutting down plants in mid-summer, or earlier
- In light soils, or where there are isolated clumps, digging out will be effective
- Remove as many of the creeping stems as possible as any piece with a node is capable of producing a new plant
- Digging up the plants can be done at any time of year
- Young seedlings can be destroyed by hoeing
- Perennial nettles are unlikely to be a persistent problem in regularly cultivated areas, except perhaps where there is a residue of seeds in the soil, or the area is adjacent to neglected land. However, annual nettles can be very numerous in cultivated soils
- Nettles cannot withstand repeated mowing
- Neglected areas can be cleared of established nettles by spraying them with a glyphosate-based weedkiller (such as Roundup Ultra, SBM Job done Tough Weedkiller (soluble sachet only) or Doff Weedout Extra Tough Weedkiller) which should be applied as a spray in June, shortly before they flower
- A second application may be necessary in September
- Check again in early spring and fork out any surviving roots
- In rough grassland, where glyphosate would kill the grass, use the selective weedkiller Vitax SBK Brushwood Killer which contains triclopyr. Two or three treatments may be needed
- Ensure you follow the directions on the packaging of weedkillers
When using glyphosate take care to avoid leaves and other green parts of all garden plants as it is not selective in action. Used with care, glyphosate is safe to use around the base of non-suckering woody plants, as long as the bark is woody, brown and mature. Glyphosate is not active through the soil and there is therefore no risk garden plants will absorb it through their roots.
Inclusion of a weedkiller product does not indicate a recommendation or endorsement by the RHS. It is a list of products currently available to the home gardener.
Weadkillers for Home Gardeners (Adobe Acrobat pdf document outlining weedkillers available to gardeners; see sections 1a and 4)
Chemicals: using a sprayer
Chemicals: using safely and effectively
Chemicals: using spot and broad-scale weedkillers
Weeds: non-chemical control