Common Name: Common Mullein
Scientific Name: Verbascum thapsus
Habitat: roadsides, disturbed areas, farmland, gravel pits, ornamental beds
Provincial Designation: Noxious
Noxious weeds are plant species designated in the Alberta Weed Control Act. Noxious weeds must be controlled, meaning their growth or spread needs to be prevented.
Common mullein is native to Asia. It was deliberately introduced to the United States as both a medicinal herb and a fish poison. Historically, it has been used to treat a variety of ailments ranging from coughs to earaches. Nowadays, it is grown as an ornamental garden plant.
Common mullein can overtake and displace native species in disturbed areas, along roadways and railways. It is a difficult plant to eradicate due to the longevity of its seeds. Its seeds can remain viable for 100 years or longer, and each plant can produce 100,000 to 175,000 seeds. Fortunately, if there is a healthy community of native plants, the seeds do not necessarily sprout. This plant may also serve as an alternate host for insect pests that feed on fruit trees.
A key characteristic of this plant is that its yellow flowers are arranged on a single 20-50 cm long spike. Individual flowers are 15-20 mm wide and mature from the bottom to top in a spiral pattern.
The leaves are covered in dense grey hairs making the leaves woolly and soft to the touch. Upper stem leaves are alternately arranged with blades of the leaves extending down along the stem. The soft leaves also give rise to regional names such as ‘cowboy toilet paper’.
The plant grows up to 2 m tall. It is a biennial, the plant produces a small round of leaves the first year but then blooms on the tall stalk the second year.
Learn more about this species:
See Fact Sheet - Alberta Invasive Species Council