How do I control new growth from feeder roots?
I have some wisteria vines (5 main ones) that are approximately 8-10 years old and growing up onto our pergola over our deck. These are huge and growing well, and I am managing the growth out of the pergola through training and pruning. This spring I planted some new greenery away from several of the main vines (approximately 1-8 feet away) and cut through some of the roots of the wisteria. Over the past couple months the cut (distal portion) of the vines are budding new sprouts from the cut end and growing new vines. How can I “kill” the distal root and keep this from happening, or can I seal or “carterize” the end to keep this from continuing? I have trimmed the new shoots right off the root several times over the last couple months but new growth continues to happen (and growing very fast, up to 12-14 inches within a couple weeks).
Certified GKH Gardening Expert
There is no fool proof way to prevent this. It is the nature of the plant (and what can make wisteria frustrating). A risky procedure is to paint the cut from removed sucker shoots with roundup. The plant will suck this in and it will kill the roots creating the suckers. The danger is that the plant will pull the herbicide into its whole system and kill the whole plant. In most cases, this method will not kill the plant, but there is a chance it could.