Q. Is ivy growing on a tree harmful to the tree?
English ivy (Hedera helix) is generally not damaging to trees in Europe, where it is a native. In the U.S., the pests and diseases that control its growth are lacking, and so the ivy can eventually overwhelm a tree.
Ivy is not a parasitic plant (i.e. its roots don't invade the tree's tissues). The hair-like root structures on ivy stems are only for support and don't take nutrients or moisture from the tree. So removing ivy from a tree trunk or letting it grow is largely a matter of personal preference.
However, when ivy grows into the upper canopy it can affect tree stability, making the tree susceptible to being blown over in high winds. Ivy in the upper canopy also crowds out the light that the tree needs for photosynthesis and competes for water and nutrients. So ivy should be kept below the crown of the tree or removed when it grows that high.
Ivy removal must be done with care so as not to damage the tree bark or injure yourself. Don't pull the ivy out of the canopy; dead branches or a hornet's nest could come down too! Use either loppers or a saw to cut the main ivy vines at ankle height and at waist or shoulder height. Carefully strip away the vines between the two cuts. Then pull out as much of the ivy as possible from the base of the tree, back to at least 6 feet from the tree base.
Leave the upper vines to die on their own. Return each year to remove any vines you might have missed and to remove new ivy growth.
For tips on a variety of gardening topics, see our Plant Information Guides.
- Courtesy of NYBG Plant Information Service