Orange Hawkweed

Hieracium aurantiacum L.

REPORT A SIGHTING

Status in Squamish:

Status in Whistler:

Status in Pemberton:

Vectors of spread:

Synonyms

Devil’s Paintbrush
Fox-and-cubs
Orange Red King Devil
Red Daisy
Orange Paintbrush
Tawny Hawkweed
Missionary Weed
Grim-the-Collier

ID Characteristics

General: Orange Hawkweed is a fast-spreading, hairy perennial plant, that can grow up to 60 cm tall. It is one of 14 non-native hawkweed species in BC.

Flowers: The flowers are bright orange or yellow clusters, and sit atop slender unbranched stems.

Stem: Stems are upright, unbranched, contain a milky sap, and are covered with black, bristly hairs.

Leaves: Leaves are hairy and arranged in a rosette at the base of the plant. Few to no leaves are found on the stem.

Similar Species

Similar native species

Scarlet Paintbrush (Castilleja spp.): a native wildflower that can be many colours including orange and red.

Orange Agoseris, also called Orange False Dandelion (Agoseris aurantiaca), is also sometimes confused for Orange Hawkweed. However, it has a taproot, unlike Orange Hawkweed which as runners and stolons. Another easy way to differentiate these orange flowers is that Orange Hawkweed often has a cluster of flowers at the end of a stem whereas Orange Agoseris only has one.

Orange Hawkweed is one of 14 non-native hawkweed species in BC; there are no orange flowering hawkweeds that are native to BC.

Report

Please report any sighting of Orange Hawkweed by clicking here.

Habitat and Origin

Orange Hawkweed was introduced from Europe to North America in 1818, most likely as a garden ornamental and as part of contaminated pasture seeds.

Orange Hawkweed is most often found in subalpine meadows and pastures. It flourishes in well-drained, coarse-textured soils and can invade natural open areas and disturbed sites, including roadsides, pastures and clearings.

Distribution

Propagation and Vectors of Spread

Orange Hawkweed spreads by vegetatively through both above-ground runners called stolons and below-ground roots called rhizomes, as well as by seed.

Seeds are primarily dispersed by wind but are also spread by machinery, footwear, as well as in contaminated soil and garden waste. Orange Hawkweed is also sometimes sold as an ornamental.

Economic and Ecological Impacts

Ecological:

Orange Hawkweed forms dense mats that outcompete native species, leading to a drastic change in vegetation, loss of forage for stock, and loss of biodiversity.

Economic:

Orange Hawkweed crowds out desirable forage plants and therefore can reduce agricultural productivity, as well as decrease land values.

What Can I Do?

Orange Hawkweed is found in the Sea to Sky region and its distribution is beyond landscape-level control. When Orange Hawkweed is present at high-priority locations and negatively impacting them, their control is considered a high priority.

Otherwise, the goal is to prevent it from spreading to new (uninfested) areas, and to control it where possible to limit its impact on biodiversity.

Learn to identify Orange Hawkweed: use the images presented on this profile page.

What to do if you spot it: You can report any Orange Hawkweed sighting by clicking here.

Play, Clean, Go. Wash equipment and vehicles at designated cleaning sites before leaving infested areas. Remove any plant material from equipment, vehicles, and clothing.

DO:

Regularly monitor properties for weed infestations.
Ensure soil and gravel is free of Orange Hawkweed before transporting.
Ensure plants (particularly flowering heads or root fragments) are bagged or covered to prevent spread during transport to designated disposal sites (e.g. landfill).

DO NOT:

Plant Orange Hawkweed in a garden, no matter how well-contained its enclosure may seem.
Move soil or gravel that has been contaminated with Orange Hawkweed.
Compost any flowering heads or plant parts. Instead, make sure to bag these plant parts and dispose of them at the landfill.

Control

Cultural Control

In soils with low nitrogen and sulphur levels, the competitive ability of grasses can be increased by applying a fertilizer with nitrogen and sulphur components.

Mechanical Control

Hand pull or dig when soil is moist.
Remove all flower heads and buds from the site since they will continue to mature even after the plant is pulled.
Mechanical control of Orange Hawkweed has had limited success since disturbing the stolons and rhizomes may only help the plant to spread.
Although mowing prevents seed production by removing flowering stems, repeated mowing encourages faster vegetative spread.

Chemical Control

Orange Hawkweed is effectively controlled by dicamba, clopyralid, picloram, and picloram + 2,4-D.
However, picloram is not suitable for wet, coastal soils.
Complete eradication is unlikely, so a follow-up with fertilizer and top dressing is required.

We recommend that any herbicide application is carried out by a person holding a valid BC Pesticide Application Certificate. Before selecting and applying herbicides, you must review and follow herbicide labels and application rates; municipal, regional, provincial and federal laws and regulations; species-specific treatment recommendations, and site-specific goals and objectives.

Biological Control

No biocontrol is available at this time; more research is required.