Common mullein

Identification & Biology
Alias' : mullein, great mullein, wooly mullein, flannel plant, velvet plant, lungwort, feltwort, Jacob’s staff, torchplant
Latin Name : Verbascum thapsus
Category : Terrestrial Plants
Description :
  • Biennial with a conspicuous, single upright stem growing 0.5 2 m tall 
  • First year mullein plants are low-growing rosettes of bluish gray-green, feltlike leaves that range from 10-30 cm in length and 2.5-13 cm in width 
  • Bolted second year mullein have alternate leaves along the stalk with leaves much larger toward the base of the plant 
  • Five-petaled yellow flowers are arranged in a leafy spike and bloom a few at a time from June-August 
  • Shallow taproot 

 

Common mullein was brought by European settlers to the US in the mid-1700’s for its use as a medicinal herb and also as fish poison. It quickly spread throughout the US and is now well established throughout North America. Mullein continues to be used as an herbal supplement to treat a variety of ailments, including chronic coughs, colds and asthma.  

Flowers mature from the base to the tip of the stalk. The length of the flowering period is a function of stalk height; longer stalks can continue to flower into early October. It is estimated that a single plant can produce 100,000-180,000 seeds which may remain viable for more than 100 years. Woodpeckers and other seed eating birds are attracted to the tall mullein spikes, especially in winter. 

Habitat

Native to the Europe, Asia and North Africa, mullein adapts easily to a wide variety of site conditions but is shade intolerant. It is frequently found along roadsides, rights-of-way and waste areas. Common mullein also grows in meadows, pastures and forestry cut blocks. It is one of the first species to appear on recently burned sites. Mullein prefers, but is not limited to, dry sandy soils. It is widespread throughout BC’s Southern Interior.  

Impact & Risks
  • Once established, mullein grows more vigorously than many native herbs and shrubs, and its growth can overtake a natural habitat in fairly short order, especially if there is continued disturbance. 
  • It does not typically invade cultivated crops, but will readily move into disturbed soils where there is limited vegetative growth and a concentration of domestic livestock. 
  • It is also thought to serve as an alternate host for insects which can attack apples and pears. 
Prevention & Mitigation
  • Do not trade or grow mullein. 
  • Avoid disturbance from machinery, vehicles and overgrazing. 
  • Common mullein is highly unpalatable to cattle and sheep so maintenance of proper stocking rates will help curtail spread in pastures or rangeland. 
  • Regularly patrol your property for mullein and immediately control or remove infestations before seed set.  
  • Cooperate with adjacent landowners and encourage them to control mullein. 
  • Because mullein seedling emergence is dependent on the presence of bare ground, seeding sites with early successional native grasses or other plants may decrease seed germination and the chance of successful emergence of mullein seedlings. 
  • Ensure soil, gravel and fill are not contaminated. Do not move contaminated soils to a new area.  
  • Avoid unloading, parking or storing equipment and vehicles in infested areas.  
Treatment & Disposal
  • Mullein can be effectively hand pulled or hoed on loose soils before seed set. Minimize soil disturbance since loose soil will facilitate mullein seed germination. 
  • If it has already gone to seed, then removed plants must be carefully bagged and taken to a landfill for burial.  
  • Where feasible, tillage provides good control of common mullein rosettes. Mowing is less effective since the rosettes will continue to develop after cutting. 
  • Chemical control is also an option. Before applying herbicides, read the label for full use and precautionary instructions.  
  • For further information on the selection and application of chemicals to protect your crop, contact AgriService BC at 1-888-221-7141 or email AgriServiceBC@gov.bc.ca.  
  • A biological control agent (natural insect enemy), Gymnaetron tetrum, was accidentally introduced to North America from Europe. The larvae of this weevil destroy up to 50% of the seeds, but not enough to keep populations in check. Another agent, the mullein moth (Cucullia verbasci) is currently being researched in the United States. 
Okanagan Distribution

Priority Level Definitions

Watch For - Poses a significant threat (very high risk) and does NOT presently occur in the region OR is relatively new to the region and is very limited in extent.
High - High risk/impact; limited population with significant potential to spread in the region.
Medium - Medium risk/impact; limited distribution – broader population distribution with potential to spread further in a region.
Low - Low risk/impact; may be widespread or not, may be of concern in specific situations with certain high values – e.g. specific agriculture crops. Some species may be treated primarily with biological control agents.