Serious weeds are overcoming our neighborhoods and forests. Two of the most serious plant pests in Oregon are rapidly becoming our most common plants: English ivy and Clematis Vitalba. If you have vines rapidly overtaking your tree, hedge, house, or shrubbery (and seeding readily in your yard, and in the neighborhood), then they are almost certainly these pests.
These vines are the most destructive plants ever introduced to Western North America and are capable of destroying all herbs, trees, and shrubs in our area. That is to say that if left alone, they kill every other plant. It simply is not safe to have them on your property. They escape by birds eating and dropping or wind dispersal of their seeds. Often they travel from your property and begin a new rapidly worsening infestation somewhere else. Both vines are more shade tolerant, drought tolerant and disease resistant than any of our native plants. They are immune to our native insects and provide little or no food for wildlife. Ivy is actually poisonous to most animals. As our forests continue to be overrun by these invasives, there will be nothing for deer and other wildlife to browse. Both plants climb trees and kill them, and then make such a dense mat of vegetation on the ground that no native plants can ever re-colonize the site again in the future.
When we tolerate these destructive plants we starve birds and animals because there are no other fruiting plants or browse for them to eat. Ivy and clematis have minimal food value. If you love birds, butterflies, trees and a diverse landscape (such as Oregon currently is) then you need to remove these destructive of pests from your property and make sure your neighbors are aware of the danger as well. Trees generally die when vines climb ½ to ¾ of the way up the trunk. A dead tree generally costs $1000 to removed.
What you can do to help: One way or another completely eliminate Clematis Vitalba and English Ivy from your property.
* Mark all native or otherwise desirable plants so you can find them (tape or spray paint works for this).
* Cut the vines on trees at 2 feet off the ground, so they wither and stop seeding overhead into your property and neighboring properties. This is effective because most of the seeds are borne on the aerial part of the plants rather than near the ground. For clematis this is easy, simply cut the vines off (they can be small or in an older plant 3 inches in diameter). For ivy you have to make sure you cut EVERY vine or it won’t be harmed by you’re efforts (this can be a dense cage around the tree). Never penetrate the tree’s bark as this can girdle the tree. This is the most important step.
*apply 1.5 strength Roundup to all the vine stubs and the remaining ivy on the ground but not the desirable plants. That is why I recommend marking them.
*If you don’t like pesticides clematis can be dug out of the ground and ivy pulled, but this is laborious
*Many plants such as trilliums and lilies go dormant in the summer or fall. Some authorities recommend spraying in early fall to avoid killing good plants. However a hot summer day in June is the best time of year to spray and effectively kills the rapidly growing plants.
*Whether you cut, pull, dig or poison these invasive plants, it will likely take a year or two to be rid of the mother plants and a few more years of making sure seedlings are eliminated when they periodically germinate from the soil.
PREPARED BY DANIEL PLATTER