The issue: Meadow hawkweed
Meadow hawkweed (Hieracium caespitosum) is a perennial forb native to Europe. It Invades roadsides, grasslands, meadows, hay fields, and lawns. This weed reproduces and spreads very aggressively from rhizomes (underground stems), stolons (runners on the soil surface) and seed. It produces very dense matts of vegetation crowding out native/desirable species. It is also considered allelopathic, meaning it produces chemical compounds that discourage the growth of other plants.
Meadow hawkweed forms basal rosettes, each of which can produce 10 to 30 flowering stems. Multiple yellow flowers (5-30) are produced on each stem and each flower can produce 12 to 50 seeds. A single rosette can produce 600- 45,000 seeds in a single year. Leaves are covered in hairs and can grow up to 6 inches long. Stems can grow up to 3 feet tall, are covered in coarse hair, and are usually leafless (may have a small leaf near the middle).
Look-a-likes: Orange hawkweed (Hieracium aurantiacum) has orange flowers while Meadow hawkweed flowers are yellow. When both species are in the rosette stage there are subtle differences. Orange hawkweed stems/stolons have more of a reddish coloring than meadow hawkweed. Meadow hawkweed rosettes have more of an erect growth habit.
Integrated pest management options:
· Prevention: Learn to identify this plant. Never transport unknown plant material. Always plant clean seed!
· Mechanical: Do not disturb soil, as this will aid in the spread of Meadow hawkweed.
· Cultural: Applying nitrogen after a selective herbicide application on pasture can help to suppress this weed.
· Biological: None.
· Chemical: The following selective herbicide active ingredients can effectively control this weed: 2,4-D, Clopyralid, and Picloram. Apply herbicides in the spring while weeds are in the rosette stage. Make sure to use a surfactant. Always read and follow herbicide label directions!