We have a river birch tree in our front yard that has a vine growing up the trunk and we have concerns that it may be harmful to the tree. Should we remove the vine?
— Abigail Anderson, Libertyville
I think there are two issues to consider concerning vines crawling up the trunks of trees — the aesthetic appearance of the vine and the health of the tree. My personal preference is to keep vines off the trunks of trees in most gardening situations because I do not like how they look growing on tree trunks. In my garden, I keep vines off the trunks of trees but that is my personal preference so if you like the look of a vine growing up the trunk then that is okay too, provided it does not overtake the tree. I recently saw a very creative use of English ivy used to train up a dead crabapple espalier on a home. The vine covered the trained branches of the espalier, and it looked great. It also saved the expense of buying a new espalier tree.
Whether a vine growing up a tree is harmful or not will depend on the vigor of the vine and the size of the tree. I have seen wisteria, Virginia creeper, and Boston ivy grow into the canopy of large shade trees and cover limbs with a very large mass of foliage. Once a vine moves from the main trunk and starts covering the leaves on branches, it will have a negative impact on the health of the tree. Significant weight can also build up on the branches over time and be an issue for any trees that are not structurally sound. Snow and ice can build up on the vine covering the tree’s trunk and branches, adding even more weight and stress on the tree. A large vine growing out from the main trunk in the canopy of a tree will increase wind load on the tree. Young trees with a trunk diameter of six inches or less can be quickly overrun by an aggressive vine. Wisteria can wind around a tree’s trunk and girdle it in time. Any vines that are overwhelming a tree in this fashion need to be removed or drastically pruned. I would suggest removing any aggressive vines to reduce future maintenance.
Vines growing on the trunk and branches can hide structural damage or potential hazards like a canker or decayed section of a branch or the trunk. A thick mat of vines covering the entire base of a tree can trap moisture and cause harm over time.
The vine growing up the trunk of the tree in your photo does not appear to be having a harmful effect on your tree, as it is just growing up the main trunk and does not appear to cover the entire base of the tree. It does not have a large mass that would put stress on the tree. I suggest keeping it pruned so that it does not get any larger.
While maintaining gardens, I often remove vines from the canopies of young trees. These vines can get into tree canopies when growing on adjacent fences or other structures. Once or twice a year, I find poison ivy crawling up the trunks of trees. This plant blends in with other vines, especially with Virginia creeper and Boston ivy and can be easy to miss with consequences as you work in the garden.
For more plant advice, contact the Plant Information Service at the Chicago Botanic Garden at plantinfo@chicagobotanic.org. Tim Johnson is senior director of horticulture at the Chicago Botanic Garden.
