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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:Up to 20 inches (51 centimeters) tall when flowering.
Leaf Description:Distinctive fuzzy leaves are dark green and oblong.
Fruit & Flower Description:Yellow flowers grow on short, leafless stalks which are covered with stiff dark hairs. The underside of its petals often have a red stripe. The flowers and seeds resemble those of dandelions.
Bloom Time:June to August

Habitat:

  • Mouse-ear hawkweed does not grow well in shady conditions.
  • It prefers to grow in open grassy areas such as fields, meadows, pastures, forest clearings, and along roads.

Impact:

  • It releases chemicals that prevent surrounding plants from growing.
  • It produces thick mats that displace 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.

Noxious Weed Listing:

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

More Resources:

Download the Mouse-ear Hawkweed Best Management Practices Factsheet

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