Common Mullein

Verbascum thapsus

Other Common Names

Woolly Mullein, Flannel Plant

Plant Category

Biennial

Invasive Description

Native to Eurasia and Africa, Common Mullein is an erect herb also known as Woolly Mullein because of its felt-like, pale gray leaves. It is a biennial that produces a rosette of soft, gray leaves in the first year and in the second year sends up a 5 – 10 foot tall bloom stalk. Yellow flowers appear from June – August.

Ecological Threat

Common Mullein was introduced by European settlers in the mid-1700s for use as a fish poison (leaves contain rotenone) and as a medicine. The main threat posed by Mullein is to natural meadows and forest openings where it colonizes very quickly. Mullein is extremely adaptable and out-competes native herbs and shrubs allowing the plant to monopolize an area very quickly. Each plant produces hundreds of seeds which can survive dormant for decades. Once colonized, it can be extremely difficult to eradicate.

How to Eradicate

For information on how to eradicate this invasive, view our statement on herbicide use and preferred alternatives for invasive plants.

Native Alternatives

You can replace this invasive plant with native alternatives. Here are some plants that make superior replacements.

Match your location on the Texas map to the color squares on the replacement plants below to find suitable replacements for your ecoregion.

Click for more details about the ecoregions

About the Region

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Salado, the location of our Fall 2025 Symposium, lies at the intersection of two ecoregions: the Edwards Plateau (Limestone Cut Plain) and Blackland Prairie (Northern Blackland Prairie).

The Edwards Plateau area is also called the Hill Country; however, this general term covers a much larger area extending farther north. Spring-fed creeks are found throughout the region; deep limestone canyons, rivers, and lakes (reservoirs) are common. Ashe juniper is perhaps the most common woody species found throughout the region. Additional woody species include various species of oak, with live oak (Quercus fusiformis) being the most common. Sycamores (Platanus occidentalis) and bald cypress (Taxodium distichum) border waterways. This area is well known for its spring wildflower displays, though they may be viewed in spring, late summer, and fall, as well. According to Texas Parks and Wildlife, average annual rainfall in the Edwards Plateau ranges from 15 to 34 inches.

The Blackland Prairie extends from the Red River south to San Antonio, bordered on the west by the Edwards Plateau and the Cross Timbers, and on the east by the Post Oak Savannah. Annual rainfall averages 30 to 40 inches, with higher averages to the east. This region is dominated by prairie species. The most common grass species include little bluestem (Schizachyrium scoparium) and Indian grass (Sorghastrum nutans) in the uplands and switchgrass (Panicum virgatum) in the riparian areas and drainages. Common herbaceous flowering plants include salvias, penstemons, and silphiums. This area has suffered greatly from overgrazing and agricultural use. Few intact areas remain, though many of the plants can be found along county roadsides throughout the region.

Our fall Symposium host chapter, the Tonkawa Chapter, includes both of these ecoregions.

Source: Wildflowers of Texas by Michael Eason