Ivy (Hedera helix) often conjures images of lush, green house plants or decorative garden vines. However, in the Pacific Northwest, ivy is far from a charming addition to the landscape. Instead, it is an invasive that aggressively overtakes our forests and threatens local ecosystems.
History of Ivy in North America
Ivy, an evergreen sprawler, climbs trees, snags, stumps, and ground surfaces, choking out plants in its path and reducing the ecosystem’s overall health and diversity. Its aggressive growth and lack of competitors often lead to monocultures of thick ivy mats.
It was first introduced to North America in the 1730s as an ornamental garden plant. However, ivy quickly took over the native ecosystems, being called “the worst invader of our West Coast forests” by Collin Varner, author of Invasive Flora of the West Coast.
An Invasion of Ivy at Pioneer Park
Pioneer Park, a 113-acre forest on Mercer Island, is a vital local habitat where deer roam, crows chatter, and pileated woodpeckers thrive. It’s a popular spot for morning runs, dog walks, and even walking horses.
However, a 2008 survey of Pioneer Park’s ecological health found ivy growing on 20% of the native canopy trees. Addressing the ivy invasion here is important for both ecological and community benefit.
Pileated woodpecker (Dryocopus pileatus) on Douglas fir (Pseudotsuga menziesii).
How to Remove Ivy
Our team is diligently restoring over 600,000 square feet of Pioneer Park by removing ivy and other invasives. Removing ivy is a multifaceted task that requires careful planning and execution. At HRS, we hand-pull ivy rather than use herbicide treatments because we’ve found that herbicide is not nearly as effective.
Here’s what we do:
- Site Assessment: We assess the area to determine the extent of the ivy infestation. This evaluation helps us decide the best tools and methods for the job.
- Tool Selection: Based on the assessment, we choose our tools (i.e., brush cutters, McLeods, or pruning shears).
- Removal Process: We meticulously pull out the ivy, removing the roots to prevent re-sprouting. This thorough approach ensures that we effectively combat the infestation.
- Disposal: After removal, we carefully pile the ivy on cardboard or downed logs to minimize soil contact and prevent any chance of regrowth. Proper disposal is crucial to maintaining the success of our efforts.
A pile of freshly pulled ivy.
Patience is the Key to Success
Northwestern salamander (Ambystoma gracile) found during ivy removal.
Completely eradicating ivy can take time, especially in heavily infested areas. However, consistent management and persistence are critical to a successful forest restoration project.
Are you looking to plant a ground cover? Go with something native! Check out our resources page to find a native plant nursery near you and help support your local ecosystem.
