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.
In the first instance, see if a non-chemical control option is feasible;
- Suckers: Remove suckers as close as possible to the point of origin on the root, scraping away soil to reach the base if necessary. Tear, rather than cut away, the shoot so that the majority of dormant basal buds are removed, thus reducing the possibility of regrowth. In grassed areas where roots are surfacing, strip off the turf and raise the soil by 5-7.5cm (2-3in) before replacing the turf in late autumn or early spring
- Seedlings: Dig out as much root as possible. Seedlings are much easier to remove than suckers and less prone to returning
- Suckers: Sever the root to isolate the sucker from the parent tree and then carefully treat the sucker with either stump and root killers containing glyphosate (e.g. Roundup Tree Stump & Rootkiller, SBM Job done Tough Tree Stump Killer (soluble sachet only), Doff Tree Stump & Tough Weedkiller and Westland Resolva Pro Tree Stump) or triclopyr (Vitax SBK Brushwood Killer). The health or stability of the tree may be affected if several large roots are severed. If treating many suckers that are still attached to a tree, be cautious, as sufficient chemical may be absorbed to cause harm to the tree. These chemicals may also kill surrounding plants if spray is allowed to drift onto beds or borders. Triclopyr (Vitax SBK Brushwood Killer) does not kill grass
- Seedlings: Chemicals are not normally needed, but you can treat freshly cut surfaces with weedkiller, as for suckers
Removal of the tree may be the only solution when suckers are too numerous. Cut down the whole tree, remove any large suckers on the stump and then apply glyphosate (e.g. Roundup Tree Stump & Rootkiller, SBM Job done Tough Tree Stump Killer (soluble sachet only), Doff Tree Stump & Tough Weedkiller and Westland Resolva Pro Tree Stump) or triclopyr (Vitax SBK Brushwood Killer) to the freshly cut surface. This helps to reduce the chance of subsequent sucker development, which can occur even some distance away. Sucker production should gradually decline as the stump and root system die.
Seedlings and suckers typically occur in places that are difficult to access, between buildings and sheds, for example. Here foliar treatment (applying it to the leaves) with weedkiller, using the products recommended above, can be effective, as there are seldom nearby plants that will be harmed. Apply weedkiller in summer. More than one application may be required.
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.
Weedkillers for gardeners (Adobe Acrobat pdf document outlining different weedkillers available for 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