Weed of the Month

Orange Hawkweed (Hieracium aurantiacum L.)
Devil's-paintbrush, Red daisy, Flameweed, Devil's-weed

Orange hawkweed is a perennial plant in the sunflower family (Asteraceae) that grows from 1-3 feet tall.  It has a shallow, fibrous root system with aboveground stolons (similar to strawberry runners) and below ground rhizomes.  Up to 10 to 30 bristly, nearly leafless stems rise from basal rosettes.  The hairy, lance-shaped leaves are 4-6 inches long and 1 inch wide.  Both stems and leaves exude milky juice when broken.  Red-oragne, one inch flowers appear May to July.  Each stem produces from five to thirty half-inch flower heads which each produce about 12 to 30 tiny, bristly, black seeds.

Hawkweed seeds are spread by wind and water, can be transported in contaminated soil, and are sometimes found in wildflower seed mixes. The seeds remain viable in the soil for up to 7 years.  Stolons form extensive mats of rosettes that prevent desirable plants from establishing or surviving.  It is unpalatable to animals and allelopathic - produces phytotoxic chemicals that inhibit other plants from regenerating.

Originally an ornamental introduced from Europe, hawkweed is an aggressive competitor of pasture and range plant species, growing in meadows, moist grasslands, rangelands, roadsides, and pastures.

Prevent the spread of existing populations and dig out and discard small patches of plants.  Be sure to dig deeply enough to remove all below ground rhizomes and roots as small pieces may develop into new plants.  Mowing is ineffective as it promotes flowering and the spread of stolons.  Manage desirable vegetation to increase its resistance to weedy invaders.

Larger patches of hawkweed can be effectively controlled using several herbicides such as 2,4-D or dicamba before bloom. A surfactant should be added to the mix to ensure adherence of the herbicide to the plant’s hairy leaves. Early season treatment applied at the rosette stage provides optimal control. Retreatment may be necessary.  BE SURE TO FOLLOW ALL PESTICIDE LABEL INSTRUCTIONS AND PRECAUTIONS

No biological control agents are currently available for orange hawkweed.  

Meadow or Yellow Hawkweed (Hieracium pratense Tausch.) also known as Yellow Paintbrush and King Devil is similar in appearance but has yellow flowers and smooth leaves.