USDA Code: VETH

Legal Status: Colorado List C

Growth form: Biennial forb

Flower: Flowers are 1 inch in diameter, five-lobed, and sulfur yellow in appearance. Flowers are grouped in a "corn cob" shaped flowering raceme.

Seeds/Fruit: Many-seeded capsules, with small cylindrical seeds. Seeds have numerous ridges and grooves.

Leaves: Leaves are alternate, overlapping, light-green, and densely woolly. The rosette leaves are covered with soft, fine hairs.

Stems: Mature plants have a single, stout, erect, stem which can grow up to 6 feet in height (Whitson et al. 1996). The stem is longitudinally ridged by the bases of leaves that continue down the stem beyond the point of attachment. The stem is densely woolly with branched hairs.

Roots: Taproot.

Seedling: Produces a rosette the first year.

Agricultural: Common mullein is not considered palatable to livestock due to its woolliness. Common mullein is not considered a serious agricultural weed since it can be controlled by cultivation (Gross and Werner 1978).

Ecological: If mullein seeds are already present in the soil, mullein seedlings are likely to be the initial colonists in newly disturbed sites because the seeds are viable for decades (Hoshovsky 1986). If the seeds are not present when the disturbance occurs or when a field is abandoned, then the limited dispersal ability of the seeds will probably not enable mullein seeds to arrive and establish while bare ground is still available (Hoshovsky 1986). Common mullein can be hard to control due to its prolific seed production (Gross and Werner 1978). It is easily outcompeted in areas with a densely vegetated ground cover but readily grows in disturbed sites (Hoshovsky 1986). It is an ephemeral plant, which is eventually displaced by other plants in undisturbed sites (Hoshovsky 1986).

General requirements: Common mullein is commonly found throughout Colorado in pastures, meadows, fencerows, waste areas, and along river bottoms. Common mullein prefers dry, gravelly to sandy, coarse-textured soils (Gross and Werner 1978).

Distribution: Common mullein is found throughout Colorado from 4500 to 9500', and is also common throughout temperate parts of North America (Rutledge and McLendon 1998).

Historical: Common mullein is native to Eurasia and was probably introduced to America as a medicinal herb. For centuries, mullein has been used as a remedy for coughs and stomach ailments. Aristotle recorded it as a fish poison and a methanol extract from the plant has been effective against mosquito larvae (Hoshovsky 1986).

Life cycle: Seeds of common mullein germinate in the early spring, forming a rosette that continues to grow into late autumn and over winter (Gross and Werner 1978). The following spring the plant produces a tall stem topped with a flowering raceme. Flowering and seed production occur from June to August.

Mode of reproduction: Reproduces by seeds.

Seed production: Common mullein may produce 100,000 to 180,000 seeds per plant (Hoshovsky 1986).

Seed bank: Seeds may remain viable for 100 years (Hoshovsky 1986).

Integrated Management Summary

As with other plants which reproduce solely by seed, integrated management efforts must include the elimination of seed production and the depletion of the seed bank. Combine herbicide or mechanical removal of rosettes with removal of seed heads from any plants that have bolted. Revise land management practices in order to promote the health of native plant comminities.

Gross, K.L. and P.A. Werner. 1978. The biology of Canadian weeds. 28. Verbascum thapsus L. and V. blattaria L. Canadian Journal of Plant Science 58: 401-413.

Hoshovsky, M.C. 1986. Element Stewardship Abstract for Verbascum thapsus, Common Mullein. Internet: 1/29/99. Available: http://www.tncweeds.ucdavis.edu/esadocs.html

Rutledge, Chris R. and Dr. Terry McLendon. No Year. An Assessment of Exotic Plant Species of Rocky Mountain National Park. Department of Rangeland Ecosystem Science, Colorado State University. 97pp. Northern Prairie Wildlife Research Center Home Page. http://www.npwrc.usgs.gov/resource/othrdata/explant.htm (Version 15DEC98).

Whitson, T.D.(ed.), L.C. Burrill, S.A. Dewey, D.W. Cudney, B.E. Nelson, R.D. Lee, R. Parker. 1996. Common mullein. Weeds of the West. Western Society of Weed Science, in cooperation with the Western United States Land Grant Universities Cooperative Extension Services, Newark CA. pg. 552.