Meadow hawkweed (Hieracium pratense)
ODA rating: A
Description
Meadow hawkweed has stems and leaves that exudes milky juice when broken. The stems are bristly and usually leafless, although occasionally a small leaf appears near the midpoint. Stems can reach three feet tall and bear up to 30 half inch flower heads near the top. Flowers are yellow and appears in May - July depending on elevation.
Impacts
Plants of the hawkweed complex produce mats of rosettes preventing desirable plants from establishing or surviving. Hawkweeds dominate sites by out competing other species for water and nutrients and by releasing alleopathic compounds from their own decaying leaves. Plants grow well in moist grassy areas but do not tolerate shade well. Hawkweeds are becoming troublesome in native meadows, prairies, pastures and lawns. Wilderness areas in the Pacific Northwest are at risk of invasion. Meadow hawkweed tends to grow in places where there isn’t constant grazing such as meadows, roadsides, pastures, lawns, and fields.
Click on image to view larger photo.
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Images courtesy of Tom Forney, Oregon Department of Agriculture
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If images are downloaded and used from the ODA web site please be sure to credit the photographer.
Introduction
Meadow hawkweed is a perennial weed that came to the United States from Europe.
Distribution in Oregon
Known to occur in Wallowa, Hood River and Clackamas counties but has potential to occur in other counties in Oregon.
Map legend
Yellow: limited distribution in county
Red: abundant in county
Grey: not known to be present in county
Biological controls
Biological control agents are not used on "A" listed weeds in Oregon. This weed is being managed for eradication or containment.
Informational Links
WeedMapper
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