Verbascum thapsus aka Mullein

Verbascum thapsus is known as common mullein or great mullein. This biennial herb belongs to the Scrophulariaceae family. Its native range includes the Azores, Europe, Siberia and the Himalaya. It is native to Britain and Ireland. It has spread across the United States and Canada. There it grows in fields, pastures, roadsides and waste ground.

The plant forms a broad leaf rosette in its first year. A tall flower stem rises in the second year. Garden plants reach about 5–8 feet [1.5–2.5 metres]. Some stems exceed 10 feet [3 metres]. Reported spreads range from about 0.3–3 feet [0.1–0.9 metres]. Thick, soft hairs cover the grey-green leaves and stems. The lower leaves grow much larger than the upper ones. Leaf bases extend down the stem, giving it winged edges. Leaves may stay green through winter, though RHS lists deciduous foliage.

Yellow flowers open along a dense raceme from June to September. Each bloom has five lobes and a shallow, saucer-like shape. The flowers have a scent and draw bees, butterflies and flies. Small, hairy brown capsules follow the blooms. Each capsule splits into two parts to release its seeds. One plant can produce up to 180,000 seeds. Most seeds fall close to the parent plant. The plant dies after flowering, but seedlings can keep it present.

Grow common mullein in full sun and soil that drains well. It tolerates light shade, poor soil and dry conditions. Sandy, stony ground suits it well. Sources report suitable soils from acidic through alkaline. Wet ground can kill the plant. Rich soil can make tall stems need support. It grows in USDA zones 3–9 and has an H6 rating. Its upright shape adds height to borders and cottage gardens. It also suits gravel gardens, meadows and dry, rocky slopes.

Spider mites can attack during hot weather. Slugs, snails, caterpillars and figwort weevils may also cause damage. Powdery mildew is another possible problem. Dense growth can crowd out native plants. Colorado and Hawaii list it as a noxious weed. Leaves and flowers have a history of herbal use. Both can serve as tea ingredients, but hazards need care. Leaf hairs can irritate, and leaves contain rotenone and coumarin. Coumarin can hinder blood clotting. Past uses include flower dyes, wax-dipped stems for torches, and dried hairs for tinder.