English ivy may be pretty, but it is an invasive species in Western Washington that has had devastating consequences to local ecosystems. Well-adapted to the mild Pacific Northwest climate, this aggressively spreading evergreen vine grows year round and tends to overtake most other species around it, having no natural ecological checks and balances to control it.
For Earth Day, April 22, take some time around your yard, neighborhood, or local park to remove ivy. It’s a great way to do your part for the planet.
It’s best to wear long pants and long sleeves, as ivy can cause an allergic reaction in some people. You’ll need the following basic tools:
- work gloves
- pruning shears
- lopping shears
- pruning saw
Starting with the Trees
Ivy is bad for trees for a couple of reasons. One, as it grows up a tree it creates a sail effect that makes the tree vulnerable to being blown over in windstorms. Two, as ivy roots its way into bark it can introduce infection and reduce the tree’s access to sun and air, promoting rot and compromising the tree’s health.
Ivy that has grown up a tree should be killed by cutting it at the base of the trunk. Using loppers or a pruning saw (depending on the thickness of the ivy vines), make a gap in the vines by cutting them at ankle height and again at shoulder height, taking care not to injure the tree in the process. Pull the ivy away from the tree between the two cuts. It’s best not to try to pull down more ivy higher up, as this can bring down dead branches, heavy dust, or even a wasp nest. The ivy will die, the leaves will fall, and eventually the dead vines will likely fall down on their own.
Pull up any ivy on the ground surrounding the tree, extending at least six feet out to help prevent it from regrowing up the tree in a year or two.
Removing Ivy From the Ground
In the forest understory, English ivy crowds out native plants and creates thick mats that often host pest animals such as the Norway rat. One might hope that at least ivy would create soil stability, but in fact it doesn’t even provide that service. Because its roots are shallow, it can actually promote slope erosion as large ivy mats are washed down by rain, carrying soil and other plantlife with them.
When removing ivy from the ground, pull up all the roots you can, taking care not to uproot nearby native plants. You can often pull up large ivy strands at a time, but you will likely need pruners to help in the process. Pulling up ivy is back-breaking work, so remember to use your legs for leverage.
Mulch the areas where you have removed ivy to prevent soil erosion, compaction, and dry out, as well as to discourage other invasive plants from seeding.
Allow ivy piles to decompose. Covering them will speed the process.
Each year, remove new ivy sprouts before they take hold. With the bulk of the work done, the need for subsequent ivy removal will diminish each year as native species spread in its place.
Photos by Julie Hall.