How do you kill trumpet vine sprouts?
Genesee County Michigan
Trumpet vine (Campsis radicans) is an aggressive deciduous, woody vine that develops orange trumpet-shaped flowers on mature plants and seed pods in the fall. It is often found growing on fences, up telephone poles, etc. Trumpet vine is native to Michigan, but can be a nuisance as you are experiencing. It is prolific, reproducing by seed, stems that root, and sprouts from the roots of current or past plants. If you have a mature vine nearby or one that was recently cut down it will produce many off shoots.
Hand pulling is an option for control, but it will continue to emerge for several years likely using this method as it is difficult to remove the whole root/rhizome system. Depending on the location of your sprouts, another option that may work for you would be to lay down weed mat and cover it with mulch. This could help reduce the number of sprouts, but they may still succeed in emerging wherever there are gaps in the mat, if for example you are working around ornamental plants, trees, etc.
Herbicides are likely the more effective option when dealing with trumpet vine sprouts. Glyphosate products (such as Roundup Weed & Grass Killer, among others) are effective, but require persistence. Woody vines can be cut and treated just above the ground and growing seedlings can also be treated. Cut stump instructions are explicitly state on the product Roundup Super Concentrate. When using products containing glyphosate there are a few important points to consider. First, as with any pesticide, remember to read and follow all labeled instructions. Second, glyphosate is a broad-spectrum herbicide, meaning it will injure or kill other plants contacted during application, so care is needed to avoid green plant material, exposed roots, and injured bark of desired plants. Third, glyphosate is relatively safe in the environment when used as labeled. It adsorbs strongly to soil in most cases (i.e. clay and organic matter), allowing even sensitive crops to be planted shortly after application; meaning no carry over issues are expected. Fourth, glyphosate alone can take up to 14 days to show full activity under ideal growing conditions. Retreatment of the area may be needed depending on the degree of infestation. Glyphosate is most effective for perennial control in the fall but can be applied anytime the plants are actively growing (temperatures consistently above 50F). Finally, be sure that the product you choose has only the active ingredient glyphosate or glyphosate + pelargonic acid. Products with additional active ingredients may have other unwanted effects and may delay the planting of other plants in the coming season(s).
Another option that may be more potent is the active ingredient triclopyr. This can be found in products such as BioAdvanced Brush Killer Plus or it can be found in combination with glyphosate in Roundup Concentrate + Poison Ivy & Tough Brush Killer. Triclopyr will persist in the soil for up to several months, so it is not recommended for areas that you will be planting desirable vegetation in soon. The concentrate of these products can also be applied using the cut stump/stem method.
With either herbicide, reapplication may be required due to the aggressive nature of trumpet vine.
With any pesticide application it is important to always read and follow all labeled instructions.
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