English ivy, Hedera helix, is a threat to trees, but it is a greater threat to the local ecosystem. This plant, in addition to other alien, invasive species, is becoming a significant problem in our parks and natural areas in all parts of Richmond.
In natural areas English ivy covers the ground and becomes a monoculture replacing smaller native plants. Other plants cannot reproduce in these ivy deserts; new trees or shrubs are unlikely to survive and natural succession is disrupted in wooded areas. Native plants that provide food and cover for wildlife will diminish over time.
When ivy encounters a vertical surface, small “rootlets” sprout from the leaf node and attach to the tree, wall , post, etc. The vine does not strangle the tree and the roots do not penetrate the bark, but the ivy does compete with the tree for water and nutrients, and heavy infestations weaken a tree. Large amounts of ivy on trees add weight making large branches or the entire tree more likely to to fall during wind events. Snow or ice are even more hazardous because accumulation on the evergreen leaves adds more weight to the tree, making failure more likely.
English ivy has two distinct phases – juvenile and adult. The juvenile form grows on the ground; as long growth continues horizontally the plant stays in this form. The adult form which will produce flower, fruit, and seed occurs only after the plant has grown up some vertical surface, which is often a tree. At this point the vine “uses” the tree to complete its life cycle, and birds will eat the fruit and then spread the seed to other locations.
1. Juvenile vine 2. Mature form with flowers 3. Fruit
Photo credit 1: Chuck Bargeton / University of Georgia / Bugwood.org) (Photo credit 2&3: Forest and Kim Starr / Starr Environmental / Bugwood.org)
English ivy should not be allowed to grow on trees both for the good of the tree and to prevent spread to other locations. If possible, do not allow this plant to grow on your property at all. See websites below for additional information.
Practice De Vine Intervention – remove English IvyIvy removal http://www.nps.gov/plants/alien/fact/hehe1.htm Ground covers to replace English ivy http://www.invasive.org/eastern/midatlantic/hehe.html Additional information http://wiki.bugwood.org/Archive:SEEPPC/English_Ivy_-_Hedera_helix_L.