Verbascum thapsus L. (Common mullein )

 


Clarence A. Rechenthin ,
USDA-NRCS PLANTS Database

 

 

 

Family: Scrophulariaceae - Figwort Family

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

Duration: Biennial

Habit: Forb/Herb


Listed by:
Invasive Plant Atlas of the US: 1
Federal Noxious Weed: 0
TDA Noxious Weed: 0
TPWD Prohibited Exotic Species: 0

Description: Common mullein is an erect herb that is also known as wooly mullein because of its felt-like leaves. First year mulleins have low growing rosettes with alternate, bluish/gray-green leaves that range from 1-5 inches wide and 4-12 inches long. The plant changes dramatically in the second year with the conspicuous 5-10 feet tall flowering stalk. The common mullein blooms bright, yellow flowers from June-August. These flowers have five petals arranged in a leafy spike. The leaves grow down the stalk in an alternate pattern with much larger leaves at the base of the plant, forming a rosette. The seeds are small, pitted, and rough with deep grooves. The seeds are able to lay dormant in the soil for decades before germinating.

History: Common mullein was first introduced to the U.S. from European settlers in the mid-1700s. It was used in Virginia as a piscicide, or fish poison. The next recorded accounts of the species are from Michigan in 1839, and then it spread to the west coast by 1876. This plant was used a medicinal herb for coughs, diarrhea, and was smoked as a respiratory stimulant. The methanol extract from the plant has also been used as mosquito insecticide. Its medicinal use is the assumed reason for its rapid spread from the eastern states to the Pacific coast.

Biology & Spread: Common mullein is a monocarpic perennial, which has a two year cycle of growth to flower and die. In the first growing season, the common mullein sprouts a taproot and a large rosette of low growing leaves. The rosette continues to increase in size until low temperatures of autumn and winter halt the growth. The second year summer, the common mullein rapidly grows its tall stalk, producing flowers from the base to the tip of the stalk. The length of the flowering period depends mostly on the height of the stalk. Taller stalks can flower continually into October. The plant then produces seeds. A single plant can produce 100,000-180,000 seeds which may remain viable for more than 100 years in the ground. After seeding the plant dies, completing the two year cycle. During the fall or winter, the seeds are released in close proximity to the parent plant, with seeds at or near the surface more likely to germinate.

Ecological Threat: The main ecological threat is to natural meadows and forest openings, where common mullein can colonize very quickly. This species is extremely adaptable and can out-compete native herbs and shrubs. This allows common mullein to monopolize an area very quickly. Another factor contributing to the spread of common mullein is the abundance of seeds the plant produces, and the fact that the seeds can survive dormant for decades. Once colonized, common mullein can be extremely difficult to eradicate from an area.

US Habitat: Common mullein can be found in any habitat that has a mean, annual precipitation of 3-6 inches, and a growing season that has a minimum of 140 days. Common mullein prefers dry, sandy soils, but will grow in many other soil types, as well. The species is not shade tolerant and colonizes well in open meadows, forest openings, pastures, road cuts, or fields. It is especially proliferate on disturbed sites, where dormant seeds can easily germinate.

Distribution

US Nativity: Introduced to U.S

Native Origin: Europe and Asia

US States: AK, AL, AR, AZ, CA, CO, CT, DC, DE, FL, GA, HI, IA, ID, IL, IN, KS, KY, LA, MA, MD, ME, MI, MN, MO, MS, MT, NC, ND, NE, NH, NJ, NM, NV, NY, OH, OK, OR, PA, RI, SC, SD, TN, TX, UT, VA, VT, WA, WI, WV, WY

Resembles/Alternatives: There are many native plant alternatives that can be planted instead of common mullein. Some of the most common used in the Eastern U.S. are black-eyed Susan (Rudbeckia fulgida), common milkweed (Asclepias syriaca), Joe-pye weed (Eupatorium dubium), butterflyweed (Asclepias tuberosa), and Ironweed (Vernonia noveboracensis). To find other alternatives, visit a local, native plant society or nursery.

Management: One of the most effective methods for prevention of common mullein is diminishing the favorable bare ground habitat needed for common mullein seed germination. This can be accomplished by sowing early succession native grasses and plants that will decrease the amount of available bare ground, and consequently decrease the successful germination rate of common mullein. Manual & Mechanical: Plants are easily removed by hand pulling because they have a shallow tap root. This method is very effective on plants that have not gone to seed. If seeds are present during removal, care should be taken to bag the entire reproductive part of the plant and dispose of it. The soil should be disturbed as little as possible to prevent loose soil, which will promote colonization of common mullein. Biological: Two biological controls have been tested in the U.S. on common mullein. The U.S. Department of Agriculture has determined the first to be specific to mullein. The European curculionid weevil (Gymnaetron tetrum) larvae matures in the seed capsule and can destroy up to 50% of the seed. The second control that has been used is the mullein moth (Cucullia verbasci.) It is effective because of its consistent feeding and development on mullein species. It is also considered to be a relatively safe control agent. **Release of biological controls into natural environments is always experimental and should be entered into only after full and careful consideration of potential non-target species impacts.  Once released into nature, biological control agents are difficult if not impossible to control. Chemical: Herbicidal control can be used in areas where mechanical controls are dangerous or not possible. An example of this would be steep slopes, where manual removal would also cause significant soil disturbance. Apply a 2% solution of glyphosate (e.g., Roundup®) or triclopyr (Garlon) and water plus a non-ionic surfactant, using a tank or backpack sprayer to thoroughly cover all leaves.  Do not over apply herbicide so that it is dripping off the leaf surface.  Use caution as glyphosate is a non-selective herbicide that may kill desirable plants, even if partially contacted by spray.  Triclopyr is selective to broadleaf plants and is a better choice if native or other desirable grasses are present.  For some sites, applications can be made during the early spring when most other non-target vegetation is dormant.  Refer to the pesticide manufacturers' label for specific information and restrictions regarding herbicide use.

USE PESTICIDES WISELY: ALWAYS READ THE ENTIRE PESTICIDE LABEL CAREFULLY, FOLLOW ALL MIXING AND APPLICATION INSTRUCTIONS AND WEAR ALL RECOMMENDED PERSONAL PROTECTIVE GEAR AND CLOTHING. CONTACT YOUR STATE DEPARTMENT OF AGRICULTURE FOR ANY ADDITIONAL PESTICIDE USE REQUIREMENTS, RESTRICTIONS OR RECOMMENDATIONS. MENTION OF PESTICIDE PRODUCTS ON THIS WEB SITE DOES NOT CONSTITUTE ENDORSEMENT OF ANY MATERIAL.

Listing Source

Texas Department ofAgriculture Noxious Plant List
Texas Parks and Wildlife Department Prohibited Exotic Species
Invaders Program
Federal Noxious Weed
Union of Concerned Scientists
United States Forest Service Southern Research Station

Text References

Data Source

USDA- NRCS Plants Database.(2013). (http://plants.usda.gov/java/profile?symbol=veth) NPS-PCA (2009). Alien Plant Working Group Fact Sheet. (http://www.nps.gov/plants/alien/fact/veth1.htm) Gucker, Corey L. 2008. Verbascum thapsus. In: Fire Effects Information System, [Online]. U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station, Fire Sciences Laboratory.(http://www.fs.fed.us/database/feis/plants/forb/vertha/all.html) Invasive Plant Atlas of the U.S.(2012)Common Mullein. (http://www.invasiveplantatlas.org/subject.html?sub=3080)

Last Updated: 2013-11-21 by Kathryn A. D'Amico