One of the most destructive groups of weeds are vines and climbers that in many cases started life as ornamental garden plants. Over the years, these vines and climbers have been spread by birds and wind and dumping over the garden fence and into local reserves, bush areas and wetlands.
Weedy vines (for example old man’s beard, banana passionfruit, and Japanese honeysuckle), can cause serious damage to the forest canopy as well as to individual trees. These vines smother the tops of trees, preventing light from reaching the leaves below, and eventually causing the forest canopy to collapse.
Several methods can be used to control weedy vines and climbers. The one you choose will depend on the size of the infestation, and how persistent the species is.
The good news is that most vines or climbers simply use the trees they are climbing over as support; once their main stems are cut and treated with herbicide, and as long as no other stems are touching the ground and can take root, their leaves and stems above the ground will die off and do not need to be removed.
Hand pulling can be used for smaller plants. Try not to disturb the soil more than necessary or new weed seeds will germinate.
While there are only a few methods of herbicide application used for vines and climbers, the specific herbicides that provide the best results can vary between weedy species. Check out the weeds advanced search on www.weedbusters.org.nz for specific herbicide rates for the weeds you are tackling.
Cutting and Treating Stumps works well on single vines or small infestations.
- First, cut the stems at ground level, leaving the cut vines up the tree to wither and die well above the ground. Avoid the temptation to pull cut vines down as you might damage the trees the vine is growing over. With some species (for example, climbing spindleberry), vines left lying on the ground may resprout and start new infestations.
- Then, either dig the stump out, or paint the cut surface with herbicide within 30 seconds of cutting to ensure that the herbicide is taken into the stump while the sap is still flowing. Use a squeeze bottle or paintbrush to just wet the surface, avoiding excess run-off of herbicide onto surrounding plants and soil. A chemical paste or gel is ideal for this control method.
Cutting, Waiting and Spraying Regrowth is best for large areas of vines, and requires a two-stage approach.
- First, cut all the vines. Leave the cut vines hanging in trees to die off.
- Then, on a second visit at a later date when the regrowth is a metre long, spray the new foliage.
Weedbusters is an interagency weeds awareness programme supported by all regional councils and unitary authorities, the Department of Conservation, Biosecurity New Zealand, Federated Farmers, Biodiversity New Zealand, NZ Landcare Trust, Nursery and Garden Industry Association, NZ Biosecurity Institute, and NZ Plant Protection Society.