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Photo Credit: Charles de Mille-Isles

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Photo Credit: Forest and Kim Starr

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QUICK FACTS

  • HPRWA SCORE 11
  • FAMILY Scrophulariaceae
  • CATEGORY Grasses & Groundcovers

common mullein (Verbascum thapsus)

Considered very invasive and is on the Hawaii State Noxious Weed List. The Division of Forestry and Wildlife of the Hawaii Department of Land and Natural Resources has designated this species as one of Hawaii’s Most Invasive Horticultural Plants.

  • Herbaceous biennial that reaches up to 10′ tall by its second year
  • Large oval-shaped leaves range in size from 3-20″ long and 1-5.5″ wide. Covered in dense woolly hairs
  • Sends up a flower stalk in the second year reaching 10′ tall, clusters of small yellow flowers grow in a random fashion along the stalk
  • Native to Europe, mullein is naturalized in temperate ares of the world and has been intentionally cultivated for its medical properties.

Harm

  • Quickly colonizes disturbed areas and out-competes native vegetation
  • Produces numerous seeds that may remain dormant for over 100 years
  • Drought-tolerant and able to withstand cold, mullein could invade native alpine ecosystem in Hawaii in places like Haleakala