Ask A Master Gardener – Magnificent Mullein

Common Mullein, Verbascum Thapsus, is a fascinating weed that made its way to the United States via settlers from Europe, northern Africa and Asia. Brought here because of its medicinal properties, it escaped the confines of their gardens and spread throughout the land. It has a laundry list of alternate names, most of which describe one feature or another, including wooly mullein, beggar’s blanket, old man’s flannel, Jupiter’s staff, St. Peter’s staff, and miner’s candle.

Although not native to the North America, mullein has made itself quite at home in its adopted land. It thrives from coast to coast in both the United States and Canada.  It grows in dry, sunny areas and will be one of the first plants to establish in a disturbed, but abandoned area.  Roadsides, railroad right-of-ways, abandoned lots, ditches, woodland edges, and pastures will all be prime mullein territory.

Considered a weed by most people today, mullein has been used for many years for respiratory ailments, pain relief, and digestive upset. The leaves and flowers are the primary components used for medicinal purposes; however, the roots are occasionally used.  The dried stalks have been dipped in wax and used for candles, the flowers have been used as dye for wool and human hair, the leaves have been packed into shoes for warmth, and the seeds have been used as a fish poison. Some gardeners intentionally put it in the landscape for the sheer beauty and magnificence of the plant itself. There is no question that it has a striking profile and an appeal all of its own.

Mullein is an herbaceous biennial. The first year it sprouts from a substantial crown and remains a low growing rosette of fuzzy, felt-like, 4-12 inch leaves that are 1-5 inches wide. Exposure to cold temperatures (vernalization) will prompt the plant to send off a 5-10 foot single, magnificent flower stalk the following year. As the stalk expands, the leaves do as well, decreasing in size as they approach the top.

The flowering portion appears on the terminal spike of the stalk and can be as much as 20 inches tall. Small (1 inch), yellow, saucer-shaped 5- petal flowers appear densely on the stalk throughout the summer, maturing from the bottom to the top.  The perky little flowers attract pollinators like bees, butterflies, and other insects, opening in the morning and closing by mid-afternoon.

The fruit is an oval, two-celled, quarter-inch capsule that will split down the middle to release hundreds of seeds. Since there are hundreds of seed capsules per plant, each plant produces hundreds of thousands of seeds each year.  The seeds have no means of propulsion, so most fall near the parent plants.  Studies have shown that the seeds can remain viable in the soil for decades.

If mullein is an unwanted weed, control is not difficult in smaller spaces. Hand pulling is easily accomplished due to the shallow tap root, especially if the soil is moist. Take care to pull the plant before it goes to seed to prevent future generations.  Disturbing the surrounding soil as little as possible and increasing the density of the turf will prevent germination of any seeds that might have been left.

Herbicides are not particularly effective against mullein because the dense hairs covering the leaves prevent uptake of the chemical.   Mowing is only effective at keeping the flower stalks from forming; the rosettes continue to form and as soon as the mowing is discontinued they will continue the growth pattern into flower spikes.

Carol Shirk

Certified Master Gardener

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