Enlish Holly - Ask Extension
Hello! I'm a student attending Mt. Hood Community College, and I'm working on a presentation for my silviculture class. I'm messaging in hopes of gett...
Knowledgebase
Enlish Holly #923745
Asked January 18, 2026, 12:57 PM EST
Hello! I'm a student attending Mt. Hood Community College, and I'm working on a presentation for my silviculture class. I'm messaging in hopes of getting a response with your experience with the invasive English Holly (Ilex aquifolium). How have you seen it impact understories?
Multnomah County Oregon
Expert Response
English holly is a common invader in forests around the Willamette Valley. Because there are still ornamental holly orchards providing the seed source, with birds spreading them into the forest.
While holly it is not officially listed as a noxious weed in Oregon, land managers often consider it to be a problem weed. Because holly is shade tolerant, it thrives under the forest canopy and it can displace native flora. I also spreads via vegetative layering of branches.
For more information on this, see the story by Clackamas Soil and Water Conservation District's weed management group at https://conservationdistrict.org/2025/december-weed-of-the-month-english-holly.html
While holly it is not officially listed as a noxious weed in Oregon, land managers often consider it to be a problem weed. Because holly is shade tolerant, it thrives under the forest canopy and it can displace native flora. I also spreads via vegetative layering of branches.
For more information on this, see the story by Clackamas Soil and Water Conservation District's weed management group at https://conservationdistrict.org/2025/december-weed-of-the-month-english-holly.html
