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The City of Portland, Oregon

Environmental Services

working for clean rivers

Phone: 503-823-7740

Fax: 503-823-6995

1120 SW 5th Ave, Suite 613, Portland, OR 97204

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Blessed Milk Thistle

Silybum marianum (blessed milk thistle)

  • ODA “B” rank species (ODA ranking page)
  • Portland 'Required Eradication' species

blessed milk thistleBlessed milk thistle presents something of a dilemma. On the one hand, it is grown for the herbal supplement market; on the other hand, it has escaped cultivation and is over-running parts of Australia and California. For the time being, milk thistle is uncommon in northwest Oregon. Still, it’s been sighted in several locations out of cultivation along the Columbia Slough and on Sauvie Island, and is relatively more common in Clark County, Washington. Blessed milk thistle is a Required Eradication species in Portland.