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Tree and treelike shrubs

Index for noxious weeds with single woody stems in King County.

Invasive trees and tree-like shrubs can have various impacts on an ecosystem. Like all invasive species, invasive trees reduce biodiversity which in turn reduces the resiliency of an ecosystem. Common holly, (Ilex aquifolium), for example, is allelopathic, which means it releases a chemical that inhibits the growth of other plants. One holly tree can spread and slowly turn an area into nothing but holly trees. This damages the health of the surrounding ecosystem from minimizing bird habitat to reducing an area’s resiliency to fire.

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Need help?

Browse the list of noxious weeds below. If you do not see your plant here, try the other categories on our main index page or email us a photo at noxious.weeds@kingcounty.gov.

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