Ohio Perennial and Biennial Weed Guide

Family:

Figwort Family (Scrophulariaceae)

Other Names:

slippery mullein.

Origin and Distribution:

Moth mullein is a native of Eurasia that was introduced into the eastern coast of North America and then spread west. It reached Pennsylvania by 1818 and was found growing in Michigan in 1840. Currently, moth mullein is distributed throughout the U.S. and southern Canada where it is found most abundantly in the east. It is naturalized throughout Ohio. Moth mullein grows mainly in waste places and also in pastures, meadows, old fields, and open woods. It prefers rich soils and is tolerant of dry, sandy or gravelly soils.

Plant Description:

Moth mullein is a biennial forming a basal rosette during the first year of growth after which it produces a flowering stalk. The rosette grows to 16 inches in diameter and is composed of dark green leaves that are deeply- and irregularly-toothed. The distinctive flowering stem is solitary, slender, erect, and 2 to 5 feet tall. Loosely clustered at the top of the stem are flowers attached to slender stalks that may be as long as the flower is wide. Flowers are 5-lobed, saucer-shaped, and white or yellow with a purplish base. Stamens emerging from the center of each flower are orange and have purple hairs. Reproduction is by seeds.

• Root System:

  Moth mullein forms fibrous roots and a deep taproot.

• Seedlings and Shoots:

  Young leaves are alternate, bright green, and have scattered minute hairs on the upper surface and edge. Veins are prominent on the lower surface. Leaves attach to the stem by way of flattened broad stalks (petioles). Young plants grow as a rosette of basal leaves.

• Stems:

  Stems are erect, slender, between 2 to 5 feet tall, and may have short hairs near the top. Stems are usually solitary but they can have a few upright branches near the top.

• Leaves:

  Leaves have irregularly toothed edges, prominent veins, lack hairs or are sparsely hairy, and are dark green. Rosette leaves are deeply toothed, oblong, up to 8 inches long, narrow at the base, and attached to the compressed stem of the rosette by way of short petioles. Leaves located on the flowering stem are alternate (1 leaf per node) and resemble rosette leaves except they are smaller, more shallowly toothed, and have sharply-pointed tips. Stem leaves lack petioles and are triangular with broad bases that clasp the stem.

• Flowers:

  Flowers attach to the flowering stem by way of slender, 1-inch-long stalks. While in bud, flowers appear button-like. After opening, the white or yellow flowers are composed of petals that are united at the base and deeply 5-lobed at the top forming a saucer-like shape less than 1 inch in diameter. Emerging from the center of each flower are 5 stamens that are orange with purple hairs. Flowers are located in loose clusters at the top of the flower stem.

• Fruits and Seeds:

  Fruits are downy capsules that are round and about 1/3 inch in diameter. Each capsule splits when mature into 2 cells filled with numerous tiny, dark brown seeds. The surface of each seed is marked with wavy ridges.

Similar Species:

Common mullein (Verbascum thapsus) is a related species that is also a biennial and similar in appearance to moth mullein. However, common mullein is taller and more robust, its foliage is covered with hairs, and its leaves have smooth edges. Compared with moth mullein, flowers of common mullein are more densely packed at the top of the flowering stem. Seeds of common mullein and moth mullein are virtually indistinguishable.

Biology:

Moth mullein blooms from June to September. There are yellow- and white-flowered forms. Both forms are found in Ohio, although the white-flowered form may occur with slightly greater frequency. Flowering can be observed to move from the bottom of the cluster towards the top. Therefore, it is possible to find plants with mature fruits at the bottom of the flower cluster, open flowers in the middle, and unopened buds at the top. Each plant produces over 1000 capsules. Seeds of moth mullein have been found to remain viable for 90 years. To control, mow close to the ground, or hoe rosette below the crown in early spring or autumn.

Toxicity:

None known.

Facts and Folklore:

• 'Blattaria' was derived from the Latin 'blatta' meaning cockroach and refers to the use of moth mullein to repel these insect pests.

• The common name 'moth mullein' comes from the curved furry stamens that resemble moth's antennae.

• Finches are reported to consume the small seeds.