Vines invading a redwood tree
I have a 15 yr old redwood tree 25' that has been almost completely engulfed by a Wisteria vine. How can I get the vine out?
Certified GKH Gardening Expert
They way I prefer is to cut it at the base. Remove as much as you can from the tree by hand, and then pour boiling water on the remaining stump. This will kill it off. Just make sure to pour slowly, so that the water stays only in the area of the wisteria. Do this for a couple of days, and it will kill off the root.
This won't be easy but it can be done! Wisteria, especially "chinese" wisteria will resprout vigorously after being cut. Your 2 options are to keep cutting it weekly until the roots become exhausted or to apply herbicide to the freshly cut stump. For this you need concentrated glyphosate, around 20%, or a concentrated product like Garlon, Poison Ivy Control and others which contains both glyphosate and triclopyr. While the wisteria is dormant is not an effective time to apply herbicide. Spring isn't either since the plant flow is from roots up to branches to push out leaves and flowers. In order to get an optimal amount of herbicide pulled down to the roots, late summer and fall are ideal. There is no need to treat the entire stump; apply herbicide to the green ring just under the bark. This thin ring is the active part where nutrients and water are flowing. Use a ladder to remove as much of the vine from the redbud as possible but do not pull the vine down. This is certain to break some tree branches. Once the dead vine dries out, it will come down much easier. This may take a year. Your redbud will be getting much more sunshine and will appreciate your effort.
More info here: https://www.gardeningknowhow.com/ornamental/vines/wisteria/controlling-or-getting-rid-of-wisteria.htm