- Name also: Black Mullein (USA)
- Family: Figwort Family – Scrophulariaceae
- Growing form: Biennial or perennial herb.
- Height: 50–100 cm (20–40 in.). Stem brownish red, stellate-haired at base, upper part sparsely haired.
- Flower: Corolla almost regular, 18–25 mm (0.72–1 in.) wide, yellow, occasionally white, fused, wheel-shaped, short-tubed, 5-lobed. Calyx 5-lobed. Stamens 5, filaments violet-haired. Pistil a fused carpel. Inflorescence spike-like, usually unbranched, sometimes lower part branched.
- Leaves: In basal rosette and alternate on stem. Basal leaves quite long-stalked, stalk winged, uppermost stem leaves stalkless, but not decurrent. Blade ovate, cordate-based, with rounded teeth (crenate), sparsely haired on top, underside felt-haired.
- Fruit: Brown, septicidal capsule.
- Habitat: Meadows, river banks, banks, roadsides, waste ground, forest margins, rocky hillocks.
- Flowering time: July–September.
Dark mullein clearly prefers old dwelling areas: it doesn’t grow in the wilderness, and it doesn’t do well in newly inhabited areas either. It most likely followed new migrants to Finland, maybe already in the Iron Age. Ancestors of modern-day Finns have also spread the species to new inhabited areas on purpose as the plant was used medicinally. It may have been valued mainly as an ornamental, however: its metre-high (3.3 feet) inflorescence is most impressive. Five chestnut-brown blotches guide pollinators into the light yellow calyx-tube and the stamens’ violet-haired filaments only add to the flower. Dark mullein dies after it has flowered, but its lateral buds grow a new stem beside the rootstock and in this way the perennial survives in quite dense stands. When it is allowed to flower in peace dark mullein self-seeds abundantly: it can produce up to 70,000 seeds! Anyone can help this handsome species stay part of Finland’s nature by refraining from picking the flowers and admiring it in the place that it is growing.
Dark mullein cross-breeds with great mullein (V. thapsus). The plants differ from each other in that great mullein’s stem leaves are mainly decurrent and its filaments are white-haired.
Nowadays there are a number of ornamental mulleins growing in the wild that have escaped from gardens, including orange mullein (V. phlomoides), white mullein (V. lychnitis) and showy mullein (V. speciosum).