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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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6. Giant Hogweed

giant hogweedGiant Hogweed (Heracleum mantegazzianum)

  • Massively tall plant (15-20 feet)
  • Large umbrella shaped flowers
  • Hollow stalks with red-purple blotches that have a single erect hair in the center
  • Large (2.5-3 feet wide) deeply incised leaves
  • Seeds almost ½ inch
  • Look for flowers from May to July
  • Likes unmaintained urban areas, vacant lots, roadsides, riparian areas

Photos by Tim Butler, Oregon Department of Agriculture

giant hogweed