Verbascum Thapsus, commonly known as mullein, is an invasive herb. Native to Eurasia, mullein is found invading most temperate climates in both hemispheres. It is unknown if this was an intentional introduction or an accident. We do know that it was established in the Kona district of Hawaiʻi sometime between 1900 and 1910. The population has exploded on the slopes of Mauna Kea and Mauna Loa since then. Haleakala has also suffered from a mullein invasion; it is actively being controlled. Mullein is on the Hawaiʻi State Noxious Weed List. The Division of Forestry and Wildlife of the Hawaiʻi Department of Land and Natural Resources has designated this species as one of Hawaiʻi’s Most Invasive Horticultural Plants.
Description and Dispersal:
- 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 and are 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
- Copious seeds are produced and are spread long distance as a contaminant in tires, shoes, and tools and by wind