Ohio Perennial and Biennial Weed Guide

Family:

Mallow Family (Malvaceae)

Other Names:

musk, musk plant.

Origin and Distribution:

Musk mallow was originally introduced as an ornamental from its native Europe into North America where it was widely planted in perennial flower gardens. However, it escaped cultivation and became a weedy pest throughout much of northeastern and northwestern United States and adjacent areas in Canada. In Ohio, musk mallow is common in the northeastern corner of the state. It is encountered in old gardens, dry grassy fields, waste places, roadsides, and railroads. It grows especially well on lime-rich soils.

Plant Description:

Musk mallow is a perennial with an upright stem that can grow 3 1/2 feet tall and large pink flowers that have 5 petals and appear in clusters at the end of each stem or individually on long stalks attached to stem nodes. Leaves located at the base of the stem are rounded and slightly lobed while leaves located further up the stem are deeply dissected into 5 to 7 toothed sections. Leaves and flowers emit a strong musky odor in warm weather or when crushed. Reproduction is by seeds.

• Seedlings and Shoots:

  Young plants grow as basal rosettes. The first two leaves are heart-shaped and have veins that are depressed above, prominent and shiny below.

• Stems:

  Stems grow between 8 to 40 inches tall. They are erect, hairy, and often branched near the base.

• Leaves:

  Leaves are alternate (1 leaf per node) and about 3 to 4 inches wide. Leaves appear either rounded with shallow lobes if located near the base of the stem or deeply divided into 5 to 7 sharply-toothed sections that appear to radiate from a common center like fingers from the palm of a hand if located further up the stem. Stalks (petioles) attached to basal leaves are long and slender while those attached to leaves located mid-way up the stem are shorter and petioles are usually lacking on uppermost leaves.

• Flowers:

  Flowers are about 2 inches wide and composed of 5 triangular petals that are notched along their outer edge. Petals are rosy or white with pink veins. Stamens (pollen-bearing structures) located in the center of each flower partially fuse into a bushy column approximately 1/3 inch long. Flowers form on long stalks and appear in clusters at the ends of stems or individually if attached to the stem at the leaf nodes.

• Fruits and Seeds:

  Numerous dry fruits unite into a circle around a common center resembling a hairy donut. Each hairy section contains a brown, kidney-shaped seed, which is 1/12 inch long and has concave sides and rounded edges.

Similar Species:

Basal and lower stem leaves of musk mallow resemble leaves of common mallow (Malva neglecta) and ground ivy (Glechoma hederacea), and upper stem leaves resemble the foliage of Venice mallow (Hibiscus trionum). Musk mallow can be distinguished by its stem leaves that are deeply divided into 5 to 7 parts while common mallow and ground ivy foliage is rounded and undivided and leaves of Venice mallow are divided into 3 parts. Also, ground ivy has opposite leaves (2 leaves per node), square stems, a creeping growth habit, and a minty odor. Common mallow flowers are much smaller than those of musk mallow and Venice mallow has yellow flowers.

Biology:

Flowering occurs from late June to September. Suggested control measures include hand pulling or, if badly infested, mowing before seeds ripen.

Toxicity:

None known.

Facts and Folklore:

• Leaves of musk mallow emit a strong, musky odor when crushed, hence its common name.

• Roots of musk mallow have been used to relieve inflammation; foliage has been used to treat colds and coughs.