Ohio Perennial and Biennial Weed Guide

Family:

Sunflower Family (Asteraceae)

Other Names:

paintbrush. YELLOW HAWKWEED: Hieracium caespitosum, field hawkweed, king devil, yellow devil, yellow king-devil, yellow paintbrush. ORANGE HAWKWEED: bouquet rouge, devil's paintbrush, grimm the collier, king-devil, orange paintbrush. MOUSEEAR HAWKWEED: felon herb, mouse bloodwort.

Origin and Distribution:

This is a highly variable genus and many species occur in North America, of which some are native and some are introduced from Europe. YELLOW HAWKWEED, ORANGE HAWKWEED and MOUSEEAR HAWKWEED are introduced species. Since their introduction, these hawkweeds have spread throughout the eastern half of the U.S. They have become especially troublesome in the northcentral U.S. They generally occur in undisturbed locations, such as lawns, fields, pastures and roadsides. YELLOW and ORANGE HAWKWEED are abundant in the eastern half of Ohio, while MOUSE-EAR HAWKWEED occurs sparsely in the northeastern corner of the state. Hawkweeds mainly grow in shallow, sandy or gravelly soils and prefer slightly acidic conditions.

Plant Description:

Hawkweeds are perennials that have coarse hairs, grow as leafy rosettes, and produce dandelion-like flowers at the tips of erect stems. They also form horizontal stems (stolons) that creep along the soil surface rooting at the nodes and giving rise to new rosettes. Hawkweeds reproduce by air-borne seeds and stolons. YELLOW HAWKWEED produces rosettes consisting of 10-inch-long leaves and bunches of yellow flowers at the tips of 3-foot-tall leafless stems. Emerging from ORANGE HAWKWEED rosettes are 2-foot-tall leafless stems with terminal groups of orange flowers. MOUSEEAR HAWKWEED rosettes are only about 3 inches across and 1 to 3 yellow flowers form at the tips of its 1-foot-tall leafless stems.

• Root System:

  The root system of YELLOW HAWKWEED generally consists of fibrous roots and slender rhizomes. ORANGE HAWKWEED and MOUSEEAR HAWKWEED have fibrous root systems.

• Seedlings and Shoots:

  YELLOW HAWKWEED seed leaves (cotyledons) are rounded, notched at the tip, and attached to the stem by way of a short leaf stalk (petiole). The next several leaves that emerge are egg-shaped, smooth-edged, hairy, and tapered to a very short petiole.

• Stems:

  YELLOW HAWKWEED stems are erect, 1 to 3 feet tall, hairy, and may have 1 to 3 small leaves attached near the base. Hairs along the upper portion of the stem are often black and gland-tipped. Emerging from the base are hairy stolons. Stems contain a milky juice. ORANGE HAWKWEED stems are erect, slender, 6 to 24 inches tall, covered with stiff hairs, and leafless except for 2 bracts located near the base. Hairs along the upper portion of the stem are often black and gland-tipped. Emerging from the base are hairy stolons. Stems contain a milky juice. MOUSEEAR HAWKWEED stems are erect, between 4 to 12 inches tall, leafless, and sticky-hairy. Hairs along the upper portion of the stem are often black and gland-tipped. At the stem bases are 1 to 3 slender stolons. Stems contain a milky juice.

• Leaves:

  YELLOW HAWKWEED leaves are slender, 10 inches long, smooth-edged, and spatula-shaped with blunt tips. Both upper and lower surfaces are covered with long bristly hairs. On the underside, the midvein is generally white. ORANGE HAWKWEED rosette leaves are smooth edged and covered with stiff hairs. MOUSEEAR HAWKWEED leaves grow densely in rosettes that are about 3 inches across. The club-shaped leaves are hairy on top and white-wooly beneath.

• Flowers:

  For YELLOW HAWKWEED, each 2/5-inch-wide, flat-topped flower head is a cluster of approximately 12 individual yellow flowers that are covered with black, gland-tipped hairs. The compact clusters form groups of 2 or more located at the tips of coarsely-hairy stems. For ORANGE HAWKWEED, numerous individual orange-red flowers are tightly clustered onto heads that are 3/4 inch across and located at the tips of leafless stems. The green bracts (floral leaves) beneath the flowers are covered with black, gland-tipped hairs. As flowers dry, they turn deep red. MOUSEEAR HAWKWEED has yellow flowers atop leafless stems. Flowers are either solitary or in groups no larger than 3. The green bracts (floral leaves) beneath the flowers are covered with black, gland-tipped hairs.

• Fruits and Seeds:

  All hawkweed species have single-seeded fruits that are cylindrical, hairless, dark brown or black, ridged, and topped by a single row of bristles.

Similar Species:

Common catsear (Hypochoeris radicata) has similar flowers on mostly leafless stems, but its leaf edges are irregularly lobed whereas those of hawkweeds are smooth.

Biology:

Hawkweeds generally produce flowers from May or June until September. Because hawkweeds can reproduce and spread by various means, they are difficult to control. Patches of the weed can be controlled by repeated cultivation, or the shallow-rooted plants can be hand-dug. Close mowing can be used to prevent seed formation. Also, management practices that increase growth of more competitive species will generally result in decreased numbers of hawkweeds. Herbicides are available to selectively control the weed.

Toxicity:

None known.

Facts and Folklore:

• The common name 'hawkweed' and the Latin name Hieracium (hierax means 'hawk') originated from a folk tale that hawks ate different parts of the plant to improve their eyesight. As a result, hawkweeds have also been called hawkbits and speerhawks.

• Several alternative common names for yellow and orange hawkweed contain the word 'devil'. These names originated with farmers who considered them troublesome weeds.

• Mouseear hawkweed got its common name because of the soft, wooly feel of its leaves.

• In past times, orange hawkweed was also called 'grimm the collier' (coalminer), because the black hairs on the stem brought to mind a coalminer after a long, dirty day of work.

• Hawkweeds were used in early Europe to treat lung disorders, stomach pains, cramps, and convulsions. They have also been used as beauty treatments.

• In the past, Native Americans used native hawkweeds for chewing gum.