Mullein

“Common Mullein is a non-native plant with a long distinguished history (see the Lore section at page bottom) that yet attaches scant respect. It is doubtful that anyone actually plants it in their garden but hopefully a few would let it grow when it shows up. The plant tends to show up all over as it is most happy to colonize roadsides and disturbed soil where a grouping of plants can make a stately impression. It is biennial and grows from a basal rosette that sends up the flower spike the second year. If the rosette is not formed early in the growing season, the young plant may not survive the winter.

The tall erect stem, up to 6 or 8 feet high, is hard to miss and the prior season stem will persist well into the summer as the stems are very rigid. It doesn’t help its reputation that it is a coarse plant, with woolly stems and leaves.

The alternate, oblong leaves are quite soft (velvety) and the lower ones up to 12 inches long, rarely with any teeth. Leaves taper in size in a gradual arrangement until the inflorescence is reached. The uppers are stalkless, the lower leaves stalked. The lower leaves will be more ovate than oblong. The undersides have hooked hairs. The leaves spiral up the stem such that the shorter upper leaves shed water onto subsequent lower leaves – all to direct the water to the roots.

The inflorescence is a densely packed spike at the top of the stem above the leaves. Occasionally additional flower spikes may develop from the upper leaf axils. Flowers overlap in clusters of 2 to 7. The spike is densely hairy.

Flowers: The 5-part flowers appear to open from the bottom upward in several spiral rows, in fact, each flower is only open for one day, then the one above opens. The yellow corolla lobes are rounded and spreading and can be up to an inch across. The five stamens have yellow filaments, orange anthers and alternate with the corolla lobes; two of the five stamens are slightly longer than the others; these are placed lower in the calyx with the 3 shorter stamens above, the arrangement such that all 5 anthers are at about equal level in the corolla throat. The 2-locular ovary and style are green with a knob-like head on the style. There are some fine yellow or whitish hair at the base of the style and on the 3 upper filaments, the lower placed two being glabrous. The female parts mature first, but if a bee does not pollinate the flower before it closes for the day, it is capable of self-pollination. The outer calyx is 5-lobed and woolly.

Seed: Fertile flowers produce a two-celled ovoid hairy capsule, 7 to 10 mm long, that contains 100+ 4-angled ridged small seeds. Each average plant has 100+ capsules. These capsules can remain on the plant over winter. Seeds can be shaken or blown out of the capsule by the wind. Seeds remain viable for years if not decades.

Subspecies: There are 3 world wide, but only one in North America – subsp. thapsus.

Habitat: Mullein grows in disturbed areas in all kinds of soils, mesic to dry conditions, but with full sun. Roadcuts and roadsides and under used pastures are common places to see it. It has a taproot and spreads by reseeding.

Names: The genus Verbascum is from, and a corruption of, the Latin name for the plant, Barbascum and the species thapsus is probably after Thapsus in ancient Africa. The common name Mullein comes from the Latin “mollis”, meaning “soft”. The author name ‘L.’ is for Carl Linnaeus (1707-1778), Swedish botanist and the developer of the binomial nomenclature of modern taxonomy. As to the basis for the other common names see the Lore section below the photo section.

Comparisons: It is unlikely you will find another plant in our area to confuse with this one. While there are 5 other species of Verbascum once reported in Minnesota, they have not been seen in years and the DNR does not track any of them on the 2019 county census” (Bebeau).