The Dirt | Weed of the Month May 2026 | Orange hawkweed (Hieracium aurantiacum)

The image discusses Orange hawkweed, an invasive plant in Oregon, highlighting its identification, issues, and management methods.
The image features vibrant orange flowers, showcasing multiple blooms with spiky green stems and buds.
Close up of orange hawkweed flowers. Photo credit: Robert L. Carr via OregonFlora.
The image shows a cluster of green plant leaves growing on a dark, rough surface, likely asphalt.
Close up of orange hawkweed leaves. Photo credit: Bruce N. Newhouse via OregonFlora.
A vibrant display of orange flowers clustered together, surrounded by green foliage in a garden setting.
Orange hawkweed monoculture. Photo credit: Michael Shephard, USDA Forest Service via Bugwood.org.
The image shows a patch of green grass with vibrant orange flowers blooming among them.
Entire orange hawkweed plant. Photo credit: R Mueller.
A vibrant field of orange flowers surrounded by trees, a small cabin, and a serene lake under a blue sky with fluffy clouds.
Monoculture field of orange hawkweed. Photo credit: M. Hafke via Invasive Species Council of British Columbia.
The image shows yellow flowers, dandelion heads, and green leafy plants among grass in a natural setting.
Hairy cats ear/false dandelion (Hypochaeris radicata) look-a-like. Photo credit: Gerald D. Carr via OregonFlora.
The image features various green plants and leaves, including ferns and other foliage, growing in a natural setting.
Hairy cats ear/false dandelion (Hypochaeris radicata) look-a-like. Photo credit: Gerald D. Carr via OregonFlora.
The image features vibrant orange flowers, showcasing multiple blooms with spiky green stems and buds.
The image shows a cluster of green plant leaves growing on a dark, rough surface, likely asphalt.
A vibrant display of orange flowers clustered together, surrounded by green foliage in a garden setting.
The image shows a patch of green grass with vibrant orange flowers blooming among them.
A vibrant field of orange flowers surrounded by trees, a small cabin, and a serene lake under a blue sky with fluffy clouds.
The image shows yellow flowers, dandelion heads, and green leafy plants among grass in a natural setting.
The image features various green plants and leaves, including ferns and other foliage, growing in a natural setting.

Our May Weed of the Month is Orange hawkweed (Hieracium aurantiacum). Known for its strinking orange flower, orange hawkweed is a perennial, stoloniferous noxious weed. It is typically found in dry, sunny, and disturbed areas such as roadsides, along railways, or in open fields. It can be tricky to identify this species when it is not in flower (primarily between June-July, but sometimes as early as May and as late as August). When not flowering, look for a basal rosette of oblanceolate leaves. The leaves have smooth margins (unlike the toothed margins of hairy cats ear, a common look-a-like), and are upright, hairy, and light green in color. Also make sure to check for horizontal runners (stolons) across the soil surface. 

Similar to may noxious weeds, this species readily takes over habitats it thrives in and can quickly dominate groundcover if left unmanaged. For small infestations, manually digging up the plant including its taproot is best. For larger infestations, consult with a licensed herbicide applicator for chemical treatment options.

This species is not known to occur in Benton County as of May 2026. However, it is present in adjacent Oregon counties, such as Tillamook, Washington, Multnomah, Clackamas, and more. Therefore, exercising vigilance for Early Detection and Rapid Response protocols is key.

If you think you have seen this plant in Benton County, report it now on the Oregon Invasive Species Hotline or call 1-866-INVADER.

Keep reading

1. OregonFlora - Orange hawkweed