Ohio Perennial and Biennial Weed Guide

Family:

Sunflower Family (Asteraceae)

Other Names:

ass's foot, bullsfoot, butterbur, clayweed, cleats, colt-herb, coughwort, donnhove, dovedock, dummyweed, fieldhove, foalfoot, foalswort, ginger, ginger root, hallfoot, hoofs, horsefoot, horsehoof, son-before-father, sowfoot.

Origin and Distribution:

Coltsfoot is a native of northern Europe and Asia that was brought to North America by early settlers. Currently, the species is naturalized throughout the northeastern U.S. Its distribution in Ohio is generally restricted to the eastern half of the state. Coltsfoot is adapted to poor soils and will grow on almost any unattended or denuded area including roadsides, pastures, open forests, stream banks, drainage ditches, and strip-mining cuts. The species prefers wet, clay soils and grows well in cool climates. Although it tolerates full sun, it grows best in part shade.

Plant Description:

Coltsfoot is a yellow-flowered perennial. Its flowers are the same color, size, and shape as dandelion flowers, and the two species are easily confused while in bloom if viewed from a distance. However, coltsfoot blooms so early that the flowers have already come and gone by the time leaves emerge. Also, coltsfoot flowers appear at the tips of 1/8-inch-thick stems that are wooly and covered with scaly bracts giving them an appearance similar to that of asparagus spears. After flowers have matured, clumps of broad, heart-shaped leaves appear on short, wooly vegetative stems. Coltsfoot reproduces primarily by horizontal creeping rhizomes (horizontal underground stems) and also by seeds.

• Root System:

  Coltsfoot forms an extensive system of thick white rhizomes (horizontal underground stems) that can spread over a large area in a very short time.

• Seedlings and Shoots:

  Upper and lower surfaces of young leaves are covered with wooly hairs.

• Stems:

  Stout, grayish-green flowering stems, covered with wooly hairs and purplish-red scaly bracts, emerge in early spring. Several flowering stems arise from one root crown. Stems are 2 to 6 inches tall when flowering begins and can reach 12 to 20 inches by the time seeds mature. After flowers mature, leaves are produced on short vegetative stems that also are covered with wooly hairs.

• Leaves:

  The broad, hoof- or heart-shaped leaves are borne on long, erect leaf stalks (petioles) arising from short vegetative stems located nearby those producing flowers. Leaves grow in the form of a rosette. As leaves mature, hairs on their upper surface fall off while the underside retains its wooly hairs. Leaves are 2 to 7 inches long and broad with shallow lobes and angular teeth on their edges. Color varies from bright green to dark or bluish green. Leaf veins radiate out like spokes from the point where the petiole attaches to the leaf blade.

• Flowers:

  Showy flower heads (1 to 1 1/4 inches wide) are borne singly at the top of scaly flower stems and consist of a disk of numerous long, narrow, petal-like, yellow ray flowers.

• Fruits and Seeds:

  As flower heads mature, they turn into white balls of tufted seeds that resemble dandelions. Seeds are 1/8-inch long, cylindrical, and yellow or reddish-brown.

Similar Species:

Coltsfoot and dandelion (Taraxacum officinale) flowers and seed-heads look similar, but dandelion flower stems are much more slender and smooth and its flowers appear at the same time rather than before leaves emerge. Coltsfoot rosettes can be distinguished from those of common burdock (Arctium minus) by the perennial rhizomes and broadly heart-shaped leaves with veins that radiate out like spokes from the point where the petiole attaches to the leaf.

Biology:

Coltsfoot flowers in March. While developing, immature flower heads often droop toward the ground. At night and on cold or cloudy days, flower heads often close. The parachute-like tufts attached to seeds aid in wind dispersal. There are reports of seeds traveling by wind as far as 8 miles. Coltsfoot seeds are only viable for one year and usually germinate the season they are produced. Since leaves appear later than flowers, many people do not associate the leaves of coltsfoot with its flowers. Coltsfoot can form extensive underground rhizome systems with many rhizomes buried 10 or more feet in the soil. For this reason, it may be difficult to control the spread of coltsfoot rhizomes using only plowing or cultivation. More effective techniques for control are improved drainage, clean cultivation, and chemical treatments.

Toxicity:

One source suggests that coltsfoot may have some toxic properties. Recent studies found that extracts produce cancer in rats.

Facts and Folklore:

• The common name refers to the shape of the leaf, which resembles a colt's hoof-print.

• The common name 'son before father' refers to the emergence of the flowers before leaves.

• The genus name 'Tussilago' is derived from the Latin word "tussis" meaning 'cough' for which the plant is supposed to provide a cure.

• Coltsfoot once served a number of medicinal uses. Leaves and roots were dried, ground, or boiled and used to make teas, candies, and tobaccos. However, recent studies in Japan found that coltsfoot flowers cause tumors in rats.