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Class A Noxious Weed

Yellow Devil Hawkweed
Hieracium floribundum

Yellow Devil hawkweed flower

Other common names: Meadow hawkweed
Plant family: Asteraceae (Compositae)
Year listed: 1997
Native to: Europe

Why is it a noxious weed?

Hawkweeds are prolific seed producers, weedy and capable of hybridizing with many exotic and probably native species. Hawkweeds are aggressive competitors of pasture, range and native plant species.

 

How would I identify it?
General Description: Perennial herb with many slender and leafy stolons (horizontal stems) at the base of the plant, and a long rhizome (underground stem). It has a well developed cluster of basal leaves at time of flowering, which is in the early summer.

Leaves:

  • basal leaves are glaucous (covered with a whitish or bluish waxy coating)
  • top of the leaf is smooth, the underside of the leaf has scattered,bristly hairs, particularly along the mid-rib
  • size ranges from 1½ - 5 inches long
  • shape is longer than wide, with the widest part being near the tip. 
  • leaf margins toward the base are also covered with long bristles
  • leaves along the stolon are more hairy than the basal leaves

Flowers:

  • yellow composites
  • with 3-50 flower heads in a flat-topped cluster
  • bracts under the flower heads have stiff hairs that are blackish and tipped with star-like glands

Stems:

  • 8 - 32 inches tall
  • sparsely scattered with long bristles that are blackish and tipped with star-like glands

How does it reproduce?
Yellow Devil hawkweed reproduces by seed, it is known for:
  • prolific seed production
  • capable of producing seed without fertilization
  • also spreads by stolons

Where does it grow?
Meadows, roadsides and fields.

What is the distribution in Washington State?
 

 

  • Distribution map not available at this time.

How do I control it?

General control methods:

Cultural: Adding fertilizer (NPK) to abandoned pastures halted or reversed patch formation by hawkweeds, particularly in areas that had a high proportion of grasses. Grass growth increased after pastures were fertilized. Fertilization as a control only worked in the plots that were dominated by established grasses.

Herbicide: Please refer to the PNW Weed Management Handbook, or contact your county noxious weed coordinator.

Mechanical: Information not available at this time.

Biological: None known.

 

Are there plants that may be confused with Yellow devil hawkweed?
This is another species of the genus that belongs to a large complex without any clear specific boundaries. Many hawkweeds are very similar in appearance. It may also be confused with dandelion. If you need help with plant identification, please contact  your county noxious weed coordinator.

For more information
For more information, download our Written Findings.

 

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Yellow Devil hawkweed infestation
Yellow Devil Hawkweed infestation.

 Last updated July 09, 2008