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Environmental Services

working for clean rivers

Phone: 503-823-7740

Fax: 503-823-6995

MAILING ADDRESS: 1120 SW 5th Ave, Room 1000, Portland, OR 97204

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How bad is it?

In the Portland metro area, milk thistle is uncommon, with sightings typically near the Columbia Slough with initial infestations showing up near transportation routes like railways. Clark County, Washington, reports active management of several infestations, as does Clackamas County. To date, aggressive management appears to be substantially reducing known patches.

Map of confirmed Blessed Milk Thistle in Portland