Great Mullein

Great Mullein

Verbascum thapsus

verbascum_thapsus_mullein_flowers_ssisc-1067x800

Status in Squamish:

NOACTION

Status in Whistler:

NOACTION

Status in Pemberton:

NOACTION
Synonyms

Great Mullein is also known as:

  • Common mullein
  • Cow’s lungwort
  • Velvet plant
  • Adam’s flannel
  • Aaron’s rod
ID Characteristics

General: Great Mullein is a robust biennial or short-lived perennial herb.

Flowers: Individual flowers are sulphur yellow, 1.5-3 cm across, and occur on a corn cob-shaped flower cluster that is 10-50 cm long.

Stem: Are single, erect, and up to 2 m tall. The stems and leaves of Great Mullein are covered in star-shaped, felted hairs, which give the plant a woolly appearance.

Leaves: Basal leaves are arranged in a rosette, and stem leaves follow an alternate leaf arrangement. Leaves are 10 – 45 cm long, lance-shaped, blueish to grey-green, and woolly.

Fruit: Small, woolly, egg-shaped capsules that contain many small seeds.

Roots: Root size and depth may vary by site, but Great Mullein generally has relatively shallow taproots.

Similar Species
Invasive:
  • Common Foxglove

    Common Foxglove (Digitalis purpurea): Foxglove leaves are more pointed and leathery than Great Mullein’s.

 

 

 

 

 

 

  • Common Comfrey (Symphytum officinale): Its leaves are larger and less hairy than Great Mullein’s.

 

 

 

 

 
Native:

  • Moth Mullein (Verbascum blattaria): While it is from the same family as Great Mullein, Moth Mullein is smaller and has white flowers.
Report

Please report any sighting of Great Mullein by clicking here.

Habitat and Origin

Great Mullein was introduced from Eurasia. It was first brought over to North America in the mid-1700’s as an ornamental, a medicinal herb, and a piscicide.

Great Mullein tolerates a wide variety of growing conditions and soils, but is tolerant of shade. It is often one of the first species to appear at burned sites, and is also found along railroads, fence rows, fields, pastures, roadsides, gravel pits and other open, disturbed areas.

Current Distribution

Propagation & Vectors of Spread

Great Mullein reproduces by seed. Each seed capsule contains hundreds of seeds, so a single plant may develop as many as 240,000 seeds. Moreover, Great Mullein seeds remain viable in the soil for over a century, so the plant quickly forms a persistent seed bank.

Great Mullein has no morphological adaptations for long-distance seed dispersal; therefore, most seeds fall very close to the parent plant. However, Great Mullein’s long-lived seed bank makes transport of contaminated soil a possible long-distance vector of spread.

Ecological and Economic Impacts

Ecological: 

  • Reduces biodiversity.
  • Unpalatable to livestock due to its woolly leaves.

Economic:

  • Established stands are extremely difficult (and costly) to control due to their abundant, long-lived seed bank.
  • Reduces crop or forage yield.
What Can I Do?

Great Mullein is found throughout the Sea to Sky Corridor, so PREVENTION of further spread is key.

 

Learn to identify Great Mullein: use the images presented in this profile page to learn how to identify Great Mullein.

What to do if you spot it: You can report any Great Mullein sighting by clicking here.

 

DO:

  • Regularly monitor properties for weed infestations.
  • Ensure soil and gravel are uncontaminated before transport.
  • Check wildflower mixes to ensure that they do not contain Great Mullein.
  • Remove plant material from any equipment, vehicles, or clothing used in infested areas and wash equipment and vehicles at designated cleaning sites before leaving infested areas.
  • Minimize soil disturbances (e.g., use grazing plants that prevent soil exposure from overgrazing), and use seed mixes with dense, early colonization (e.g., alfalfa or barley) to revegetate exposed and resist invasion.
  • Ensure plants (particularly flowering heads or root fragments) are bagged or covered to prevent spread during transport to designated disposal sites (e.g., landfill).

 

DO NOT:

  • Do not unload, park or store equipment or vehicles in infested areas; remove plant material from any equipment, vehicles or clothing used in such areas and wash equipment and vehicles at designated cleaning sites before leaving infested areas.
  • Do not plant Great Mullein in a garden, no matter how well-contained its enclosure may seem.
  • Do not move soil that has been contaminated with Great Mullein.
  • Do not compost!

 

Control

Mechanical

  • Hand-pull plants that grow on loose soil; for harder soils, use a spade or shovel to cut the taproot.
  • Try to minimize soil disturbance, since it will facilitate seed germination.
  • If blooms or seed capsules are present, make sure to remove and bag them before disposing of them in a landfill.
  • Mowing new plants (when they are 30-60 cm tall) can reduce population and seed production for the season, especially in dry years.

Chemical

  • Herbicide application is most effective when the rosettes have 6-12 leaves but before the stem starts to grow, usually in May to mid-June.
  • Due to the woolly leaves, the use of a surfactant is recommended.
  • Consider re-treating sites more than once, to tackle the long-lasting seed bank.
  • Aminopyralid + metsulfuron methyl; aminopyralid; metsulfuron methyl; chlorsulfuron; picloram; picloram + 2,4-D; glyphosate; chlorsulfuron + metsulfuron methyl; and aminopyralid + 2,4-D are all considered effective on Great Mullein.
  • Note that picloram is not suitable for wet, coastal soils.
  • We recommend that any herbicide application is carried out by a person holding a valid BC Pesticide Applicator Certificate. Before selecting and applying herbicides, you must review and follow herbicide labels and application rates; municipal, regional, provincial and federal laws and regulations; species-specific treatment recommendations, and site-specific goals and objectives.

Biological

Some biological agents exist, including seed feeding weevils (Rhinusa tetra), curculionid weevil (Gymnaetron tetrum), and mullein moth (Cucillia vergasci), which is currently being studied in the US.

References