Pilosella aurantiaca

It is a low-growing plant with shallow fibrous roots and a basal rosette of elliptical to lanceolate leaves 5–20 centimetres (2.0–7.9 in) long and 1–3 centimetres (0.39–1.18 in) broad.[4] All parts of the plant exude a milky juice. The flowering stem is usually leafless or with just one or two small leaves. The stem and leaves are covered with short stiff hairs (trichomes), usually blackish in color. The stems may reach a height of 60 centimetres (24 in) and have 2–25 capitula (flowerheads), each 1–​2 ¹⁄₂ cm diameter, bundled together at the end of short pedicels. The flowers are orange, almost red, which is virtually invisible to bees, yet they also reflect ultraviolet light, increasing their conspicuousness to pollinators.[5] The flowers are visited by various insects, including many species of bees, butterflies, pollinating flies.[5] The flowers themselves come in a range of colors from a deep rust-orange to a pure yellow and often show striking gradients of color.

The plant propagates through its wind-dispersed seeds, and also vegetatively by stolons and shallow rhizomes.

Pilosella aurantiaca showing dense habit and flowering.

P. aurantiaca is widely grown as an ornamental plant in gardens for its very decorative flowers. It is often used in wildflower gardens because its bright orange flowers are highly attractive to a wide array of pollinators.[6]

Orange hawkweed is currently the only hawkweed considered regionally invasive in areas of British Columbia, Canada. It is considered invasive in the East Kootenay, Central Kootenay, Columbia-Shuswap, Thompson-Nicola, Bulkley Nechako, and Cariboo Regional Districts. Invasive hawkweed can replace native vegetation in open, undisturbed natural areas such as meadows, reducing forage and threatening biodiversity.[7] In Victoria and NSW, Australia, hawkweed species are declared as "State Prohibited Weeds" and are controlled under The Bio Security Act 2015. Orange hawkweed is also considered an invasive species in some states in the United States of America, such as Wisconsin and Minnesota.[8][9] Currently there are several eradication programs operating (often employing volunteers) to locate, prevent the spread of and eradicate any Pilosella or Hieracium plants.