Advice
RHS Help & Advice
Bramble, nettle and thistle control
Brambles
(Rubus fruticosus), stinging nettles
(Urtica dioica) (right) and creeping thistles
(Cirsium arvense) are all nuisance perennial
weeds that can quickly colonise neglected ground.
Contact herbicides give very little control - simply scorching the foliage - as these weeds all have the ability to regenerate new top growth from their perennial root system.
Consequently systemic weedkillers that travel down into the roots of the weeds are recommended for the control of these persistent weeds. The most effective are based either on glyphosate, ammonium sulphamate* (such as Root Out or Deep Root) or triclopyr (specifically SBK Brushwood Killer).
Each of these active ingredients has their own properties. For example, glyphosate and ammonium sulphamate* are non-selective whereas SBK Brushwood Killer is harmless to grass. Additionally, glyphosate doesn't linger in the soil whereas ammonium sulphamate* and SBK Brushwood Killer remain in the soil for six to eight weeks. Check the manufacturer's recommendations for individual herbicide properties and methods of application.
* The active ingredient ammonium sulphamate and all products containing it are being withdrawn. It can continue to be sold until 22 November 2007, but can be stored and used until 22 May 2008.