English ivy is a woody, climbing vine that has been used extensively in the Pacific NW. Research has shown the problem ivies to be Hedera hibernica, Hedera helix 'Baltica', 'Pitttsburgh' and 'Star'. The ivy basically strangles the trees and suffocates them, ultimately causing soil erosion when the trees fall or die.
Why is English ivy a problem?
English ivy is not native to the United States and has no natural predators or pests to keep it in check. It easily escapes from planting areas and invades natural areas, parks and urban forests. It creates "Ivy Deserts" - areas so dominated by ivy that no other vegetation survives. Ivy affects trees negatively, especially when it climbs into the canopy. By adding weight to limbs and reducing air flow around the tree's trunk, ivy makes a tree more susceptible to canopy failure, wind stress and disease. It can also strangle trees around their base and reduce the flow of nutrients up and down the tree.English ivy does not provide a significant food for native wildlife, but does provide habitat for rats.
What can you do?
Do not plant ivy. Remove ivy, especially from vertical surfaces where it seeds and is spread further by birds. Remove ivy from your yard. Join community out-reach and volunteer-based removal work parties.
Take part in No Ivy Day 2010 work day, on Saturday October 9th. Mark your calendars now!
You can help restore the native habitat of Forest Park and other natural areas with efforts in removing invasive plants, youth development programs, environmental education, and community participation, promoting research, providing technical assistance, and seeking relevant societal changes.