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Mouse-ear Hawkweed (Hieracium pilosella)

SWCD Branded Separator
Mouse-ear Hawkweed flowers. Photo Credit: Janie Marlow, NameThatPlant.net, Bugwood.org

Also known as: Mouseear hawkweed

Mouse-ear hawkweed is a low growing perennial with distinctive fuzzy leaves. While more common in Western Washington state, one infestation has been identified in neighboring Yamhill County.

Description:

Life Cycle:Perennial (life cycle lasts more than one year)
Early Detection and Rapid Response species:Yes
Height:3 to 10 inches (7 to 25 centimeters)
Leaf Description:Distinctive fuzzy leaves that grow along stolons A horizontal stem that runs along the ground and takes root at certain points to form new plants..
Fruit & Flower Description:Yellowish-white flowers are produced on short, leafless stalks which are covered with stiff dark hairs. The flowers resemble those of dandelions.
Bloom Time:May to June

Habitat:

  • Prefers to grow in open grassy areas such as fields, meadows, pastures, forest clearings, and roadsides.
  • It does not grow well in shady conditions.

Impact:

  • Produces thick mats that prevent other plants from establishing or surviving.
  • It displaces desirable pasture species and thrives in over-grazed pastures.

What you can do about it:

  • If you think you’ve found mouse-ear hawkweed anywhere in Oregon, please report it to the Oregon Invasive Species Hotline.
  • Do not mow mouse-ear hawkweed flowers, this only stimulates the plant to re-grow.
  • If there are only a few plants, hand digging is an effective option, but the entire plant must be removed. Once removed, throw away the plant parts in a plastic bag in the trash— not your yard waste bin or home compost.

Look-alikes:

Dandelions. (c) Gerald D. Carr, courtesy of OregonFlora

Dandelions (Taraxacum officinale) produce similar looking flowers to mouse-ear hawkweed. Dandelions leaves are more deeply cut and do not have fuzzy leaves that are symbolic of mouse-ear hawkweed.

Noxious Weed Listing:

State of Oregon:Class A
State of Washington:Class B

More Resources:

  • Pacific Northwest Weed Management Handbook: Mouseear hawkweed
  • University of California, Weed Research & Information Center: Hawkweeds