Hello everyone, my name is Nick Race, and I'm the invasive plant coordinator resource assistant on the Pike National Forest. If you caught my blog post last month, I talked a bit about what invasive plant management is, some of the impacts invasive plants have on our public lands, and some challenges that come up when managing them on a landscape scale. In this post I am going to shift focus and talk about one invasive plant species in particular, orange hawkweed (Hieracium aurantiacum).
Orange hawkweed aka “fox and cubs” or “devils paintbrush” is a small perennial forb native to the sub alpine regions of Europe. It has furry leaves, that form rosettes along the ground and release a milky white sap when broken. When flowering it puts out a furry stem 10 to 20 inches in height with a cluster of 5 to 35 flame colored flower heads. It is a beautiful plant, and this beauty likely contributed to its initial introduction in the 1800s as an ornamental plant and continues to contribute to its spread throughout the US.
Flame colored flower cluster of orange hawkweed
Within the state of Colorado, orange hawkweed is classified as a list A noxious weed. List A species are plant species that the state designates for immediate eradication where found. Colorado has a three tiered noxious weed list and if you are curious you can learn more about it here. Usually list A species have the potential to create serious problems in either agricultural or natural lands within the state, but are not so widespread yet that they have a higher chance of being successfully eradicated than either list B or C species. Orange hawkweed spreads vigorously from stolon’s, creeping rhizomes, and wind/animal dispersed seeds. Just one plant can cover an area of 2 to 3 feet in diameter in its first year of growth. In the Pike National Forest, orange hawkweed has been found inhabiting wet meadows, seeps, riparian areas, pastures and, even granite rock cliffs to about 9,000 feet in elevation, in habitats where uncommon or rare native plants can be found. Thus, the biggest threat that comes from orange hawkweed establishment is a loss of native plant diversity in these critical habitats of the national forest.
Orange hawkweed basal rosettes forming a dense mat
Currently, known infestations of orange hawkweed are being managed with herbicide applications via backpack sprayer. Small clusters or individual plants are extremely difficult to locate until flowering occurs due to its basal growth habit. Since this plant flowers from June to September depending on elevation, we found that repeated bi-monthly site visits allow us to find plants that may not have been flowering during an earlier treatment. It is likely that there are infestations of orange hawkweed in places of the forest that have not been documented yet, and that is where education of the local public comes into play. One of our newest (and largest) infestations was reported to us by a hiker who happened to know what orange hawkweed looked like. One of my main goals as invasive plant coordinator is to continue to educate more people about invasive plants and their impacts. Whether they work for the forest service or just recreate in our public lands, every person can help stop the spread of invasive plants with a little bit of knowledge.
A singular orange hawkweed plant revealing its location through dense grass
Agency: U.S Forest Service
Program: Resource Assistant Program (RAP)
Location: Rocky Mountain Regional Office
