Mouse-ear hawkweed (Hieracium pilosella) is an invasive perennial herb in the daisy (Asteraceae) family. It is native to Europe and Asia but now occurs as a serious weed in New Zealand, Canada and USA. It is one of several Hieracium species, including orange hawkweed (Hieracium aurantiacum), now present in Australia. The weed is a major threat to south-east Australia and, as such, all hawkweed species are Class 1 noxious weeds in NSW. In New Zealand, mouse-ear hawkweed is considered the most invasive of the nine hawkweed species present there, significantly decreasing carrying capacity in pastoral areas of the South Island high country.
The herb has a rosette habit, from which stolons to 30 cm arise to produce new rosettes, which can form dense mats. In addition to this vegetative reproduction, the species produces solitary yellow flower heads on each flowering stem that mature to release small wind-dispersed seeds. Other diagnostic features include a red stripe on the underside of petals; leaves and stolons covered in long simple hairs; and leaf undersides being lighter in colour and covered in felt-like hairs.
A small infestation of mouse-ear hawkweed was discovered in December 2014, near Charlottes Pass in the Main Range of Kosciuszko National Park. The NPWS has an active control-and-detection program under way to eradicate this threat. This is in addition to the orange hawkweed eradication program, which is active in another part of Kosciuszko National Park.
In Australia, this plant is also known to occur in Victoria (Falls Creek), where the species is also under eradication.
For more information, a Hawkweed Alert has been developed to assist with the identification and reporting of mouse-ear and orange hawkweed. A video produced by the Victorian Government also describes how to identify hawkweeds.
Page last updated: 12 February 2015