Species specifics: Common mullein

Fast facts

Found in all 50 states of the United States, this invasive weed is considered noxious in many states
Pioneer weed species that establishes quickly in recently disturbed, bare ground in direct sunlight
A single plant can produce almost 200,000 seeds that can remain viable for up to 100 years
Biennial with notable woolly leaves that establishes as a rosette in the first year and can reach up to 6 feet or more in the second year of growth

What to look for

Common mullein (Verbascum thapsus), also known as great mullein or woolly mullein, is a prolific herbaceous spring-germinating biennial that is common across the United States and is considered a noxious weed in many states and counties.

Notable characteristics of the weed include light green, thick and fuzzy leaves starting as a rosette that aggressively grows during the first year of establishment. By the second year, common mullein will produce a single, stout upright stem that will grow 2 to 6feet tall with woolly leaves that overlap and alternate upward. Each plant develops a deep tap root that can be pulled during the rosette stage or before seed production to help with control.

As the growing season progresses in its second year of establishment, the plant will develop long terminal spikes that bear sulfur-yellow, sessile flowers that are five-lobbed and over 1 inch in diameter at the top of the stem. The flower bract contains two-chambered fruit that yield numerous tiny, angular dark brown seeds. Each plant can produce hundreds of thousands of seeds that generally fall within 5 meters of the parent plant and are viable for up to 100 years.

Considered a pioneer species because it is often one of the first species to grow in disturbed areas, new plants emerge in spring from seeds in freshly disturbed ground that is in direct sunlight. However, it can be outcompeted by more desirable plants and forages over time if infestations are small or large colonies do not get established. With a preference for well-drained, dry and sandy or gravelly soils, it’s common to find the weed infesting burned areas, recently cleared ground, including forests, heavily overgrazed pastures or barren turnouts, abandoned croplands and wastelands.

Where it is found

Once localized to the East Coast, this weed has now spread throughout much of North America. Colorado, Hawaii, Nebraska and Wyoming while other states such as Montana and Nebraska identify it as noxious across numerous counties.

How to treat it

During the rosette stage or up to a 6-inch bolt, apply 16 to 20 fluid ounces of DuraCor® herbicide per acre.

Because of common mullein’s woolly leaves, a surfactant is necessary to help herbicide absorption when treating once the plant exceeds 6 inches in height. For ground applications, apply DuraCor herbicide with a methylated seed oil (MSO) at 1% volume/volume (v/v) (15 gallons per acre or higher to optimize control). For aerial applications, apply DuraCor herbicide at 20 fluid ounces per acre plus Metsulfuron-methyl at 0.5 ounce per acre plus MSO at 1% v/v.

Always read and follow label directions. Under normal field conditions DuraCor® is non-volatile. DuraCor has no grazing or haying restrictions for any class of livestock, including lactating dairy cows, horses (including lactating mares) and meat animals prior to slaughter. Label precautions apply to forage treated with DuraCor to manure and urine from animals that have consumed treated forage. DuraCor is not registered for sale or use in all states. Contact your state pesticide regulatory agency to determine if a product is registered for sale or use in your state.