Backyard Invasion - Columbia Land Trust
Orange hawkweed (Hieracium aurantiacum)
A recent Backyard Habitat Certification Program site visit led to the discovery of orange hawkweed, an unusual, pretty, but invasive plant.

Gaylen Beatty, Backyard Habitat Certification Program manager for Columbia Land Trust, and Cindy Ellison of Friends of Tryon Creek were conducting a local site visit earlier this fall when they came across an attractive but unusual flower. A closer look at the plant’s bright orange, showy flowers confirmed their suspicions: they’d found orange hawkweed (Hieracium aurantiacum), an A-list noxious weed invasive to the Portland area.

Orange hawkweed has only been found in five sites in Portland. This recent discovery was made in Multnomah County near a couple natural areas including Tryon Creek State Natural Area. It’s an Early Detection, Rapid Response Weed (EDRR), meaning all detected instances of the plant need to be treated as quickly as possible to prevent spreading.  Thankfully, West Multnomah Soil & Water Conservation District sent staff out to treat the infestation.

Noxious weeds like orange hawkweed are spread by gardeners who find the flowers attractive and who have SO much of the plant that they offer it to neighbors and friends. Pro tip: if someone offers you a plant that they have “LOTS of” in their garden, do your research before accepting it.

According to the City of Portland’s website, orange hawkweed is known to form dense patches that begin in open, disturbed areas. In eastern Oregon, orange hawkweed is known as a rangeland weed. In the greater Portland area, it seems to find a similar home in turf and lawns.

It has persistent root systems, which do not respond to some herbicide treatments, making management of established populations difficult. Orange hawkweed infestations can lead to reduced plant and animal diversity as other species are choked out, as well as diminished agricultural value. Orange hawkweed is primarily spread by fluffy seeds, although new plants are often formed by difficult-to-see above-ground runners. Using these two strategies, orange hawkweed is able to quickly fill in open spaces and resist management.

Detecting extremely problematic noxious weeds before they have a chance to spread is just one way in which the Backyard Habitat Certification Program, which Columbia Land Trust runs in partnership with the Audubon Society of Portland, helps build healthier habitats for both people and wildlife. If you’re curious about what might be hiding in your backyard, or you’re just eager to create, beautiful, resilient, native habitat for area wildlife, visit backyardhabitats.org today!

On behalf of Columbia Land Trust and the Audubon Society of Portland, we’d like to thank our friends and partners at Friends of Tryon Creek for helping us deliver the Backyard Habitat Certification Program in Lake Oswego, and to West Multnomah Soil & Water Conservation District for responding for addressing invasive weed issues, while also providing a host of educational opportunities for those looking to create backyard habitats.