common mullein

Verbascum thapsus L.

U.S. Nativity: Exotic
Habit: Herb

Synonym(s): big taper, flannel mullein, flannel plant, great mullein, mullein, velvet dock, velvet plant, woolly mullein

Verbascum thapsus is a biennial forb native to Eurasia and Africa. Plants are unbranched and can grow to more than 6.6 ft. (2 m) tall.
First year plants develop as a basal rosette of felt-like leaves. Basal leaves are 4-12 in. (10.2-30.5 cm) long, 1-5 in. (2.5-12.7 cm) wide and covered with woolly hairs. Cauline (stem) leaves are decurrently alternate and decrease in size towards the apex.
The plant bolts in the second year. Flowering occurs in June to August, when five-petaled, yellow flowers develop at the apex of the shoot. Plants die after flowering.
The fruit is a ovoid capsule that splits, releasing 100,000 to 180,000 seeds from the parent plant, that germinate in water.
Ecological Threat
Once established it grows quickly to form a dense ground cover. It can overtake and displace native species. At the high densities, it appears to prevent establishment of native herbs and grasses following fires or other disturbances. Verbascum thapsus occurs in areas with an average annual precipitation of 20-60 in. (0.5-1.5 m) and a 140-day growing season. It prefers well-drained soils with pH 6.5 to 7.8. It prefers dry sandy soils but can grow in chalk and limestone. It can be found in neglected meadows, forest openings, pastures, fence rows, roadsides, and industrial areas.

Identification, Biology, Control and Management Resources

Weeds Gone Wild: Alien Plant Invaders of Natural Areas - Plant Conservation Alliance
Element Stewardship Abstract - The Nature Conservancy
Weed of the Week - USDA Forest Service