- Name also: Common Mullein, Aaron’s Rod
- Family: Figwort Family – Scrophulariaceae
- Growing form: Biennial herb.
- Height: 30–150 cm. (12–60 in.) Stem grey, felt-haired.
- Flower: Corolla almost regular, 12–25 mm (0.48–1 in.) wide, yellow, fused, wheel-shaped, short-tubed, 5-lobed. Calyx 5-lobed, densely haired. Stamens 5, of which 2 long and 3 short; long stamen filaments often sparsely haired, with short, white hairs. Pistil a fused carpel. Inflorescence spike-like, usually unbranched.
- Leaves: In basal rosette and alternate on stem. Basal leaves short-stalked, stem leaves decurrent. Blade elliptic–ovately elongated, blunt-tipped, both sides densely haired, with entire or shallowly toothed margin.
- Fruit: Hairy, approx. 5 mm (0.2 in.) long, septicidal capsule.
- Habitat: Meadows, dry meadows, slopes, rocky outcrops, roadsides, railway embankments, waste ground.
- Flowering time: July–September.
In its first year great mullein grows a large, dense, woolly leaf rosette, and in its second year it develops its flowering stem and stretches upwards, reaching even the same height as a person. Each flower is itself only open for a couple of days, but the flowering stem as a whole can last for months. The dead stem stays erect throughout the next winter or two. The Finnish name for the plant comes from the fact that in olden days they would be covered in pitch or tar and used as torches, and this is also the basis of its majestic old name ‘candela regia’, meaning ‘king’s candle’. Mulleins were later used as lamp or candle wicks and burned as tinder. Attempts were also made to smoke mulleins in pipes – the leaves were used like tobacco, apparently to help treat a cough because the species have a strong reputation for being able to cure lung diseases. It seems to have been important in its day and was used as a versatile medicinal herb: many old Finnish names refer to its abundant beneficial properties; it was believed to be a highly potent medicine.
Mullein is often found around inhabited areas. Great mullein’s relative dark mullein (V. nigrum) has violet-haired stamens, its leaves do not extend decurrently along the stem, and the plant is in general dark green.