Hieracium aurantiacum, Orange Hawkweed

Gardens & Landscapes, Invasive Species, Extension Master Gardener January 28, 2013 Print Friendly and PDF

Invasive Species: Hieracium aurantiacum, Orange Hawkweed

Orange hawkweed is an invasive perennial plant that can grow up to 11.8 to 23.6 in. (30 to 60 cm) tall and produces a milky sap. Leaves are mostly basal, elliptical, 2 to 8 in. (5 to 20 cm) long, 0.4 to 1.2 in. (1 to 3 cm) wide, and covered with short, stiff, black hairs. Flowers are orange to red, have square-edged petals, and appear in May to June on leafless flower stalks. Dandelion-like fruit have a white pappus attached that aids in wind dispersal. Orange hawkweed is native to Europe and occurs in grasslands.

What are invasive species and why should we be concerned about them? 


Taxonomy: Scientific and Common Names for This Species

Asterales > Asteraceae > Hieracium aurantiacum L.

Hieracium aurantiacum - USDA PLANTS Profile

Distribution Maps

Orange hawkweed - The reported distribution of this invasive species across the United States. (Source: Invasive Plant Atlas of the United States)

Up-to-the-minute distribution maps and why they are important

Reporting This Invasive Species

What is the best way and place to report the occurrence of an invasive species? 

 How to report an invasive species sighting to EDDMapS - Early Detection & Distribution Mapping System

EDDMapS - Report an invasive species to EDDMapS

Cooperative Extension Offices - Find your local Cooperative Extension office on this map provided by USDA

How to Identify

This invasive species can be identified by looking for the characteristics described in the paragraphs that follow.

Plant

Orange hawkweed is an invasive perennial plant that is 11.8 to 23.6 in. (30 to 60 cm) tall and produces a milky sap.

Michael Shephard, USDA Forest Service, bugwood.org Jamie Nielsen, University of Alaska Fairbanks, Cooperative Extension Service, bugwood.org

Foliage

Leaves are mostly basal, elliptical, 2 to 8 in. (5 to 20 cm) long, 0.4 to 1.2 in. (1 to 3 cm) wide and covered with short, stiff, black hairs.

Michael Shephard, USDA Forest Service,  bugwood.org John Cardina, Ohio State University, bugwood.org

Flower

Flowers are orange to red, have square-edged petals, and appear in May to June on leafless flower stalks.

Michael Shephard, USDA Forest Service,  bugwood.org Joseph M. DiTomaso, University of California-Davis, bugwood.org

Fruit

Dandelion-like fruit have a white pappus attached that aids in wind dispersal.

Michael Shephard, USDA Forest Service,  bugwood.org Ken Chamberlain, Ohio State University, bugwood.org

 

Native Species That Resemble Orange Hawkweed

All species within this genus, including natives, are designated as noxious weeds.

Hieracium gronovii, gronovius hawkweed - Images at invasive.org

James H. Miller & Ted Bodner, Southern Weed Science Society, bugwood.org James H. Miller & Ted Bodner, Southern Weed Science Society, bugwood.org

 

- Images at invasive.org

   
bugwood.org bugwood.org

 

Additional Images for Orange Hawkweed

Orange hawkweed - Images at Invasive.org

 

Learning Resources for Orange Hawkweed

 

Additional Information, Biology, Control and Management Resources

Control and management recommendations vary according to individual circumstances. Location, habitat, weather, and a variety of other conditions are factors that help determine the best treatment choice. To find the safest and most effective treatment for your situation, consult your state's land-grant institution. If you will use chemicals as part of the control process, always refer to the product label.

United States Land-Grant University System - Find your land-grant university's College of Agriculture, Cooperative Extension Service, or other related partner on this map provided by USDA.

Weed of the Week - USDA Forest Service

Fire Effects Information System - USDA Forest Service

Hieracium aurantiacum (Orange Hawkweed) - Minnesota Wildflowers

Montana War on Weeds - Montana Department of Agriculture

Noxious Weeds - King County


 

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This work is supported by the USDA National Institute of Food and Agriculture, New Technologies for Ag Extension project.