Family: Asteraceae

Origin, Description & Uses:
Hypochaeris radicata, commonly known as gosmore or hairy cat’s ear, is a low-growing perennial herb native to Europe, western Asia, and North Africa. It has since spread widely across temperate and subtropical regions worldwide, including all major Hawaiian Islands, where it is now naturalized. The plant forms a basal rosette of hairy, deeply lobed leaves and produces bright yellow, dandelion-like flowers on tall, slender stems. It thrives in disturbed areas such as pastures, roadsides, lawns, and open fields. While sometimes considered a minor forage plant for livestock and occasionally used in traditional herbal remedies, it is more often regarded as a weed due to its persistence and ability to colonize managed landscapes.

Risks & Threats:
In Hawai‘i, Hypochaeris radicata is naturalized and exhibits traits that are cause for concern in tropical island ecosystems. It produces abundant wind-dispersed seeds, establishes readily in disturbed and undisturbed habitats, and can form dense populations that compete with native vegetation and desirable pasture species. Its adaptability to a wide range of environmental conditions allows it to spread across elevations and habitat types, potentially altering plant community structure and reducing biodiversity. Because of these invasive characteristics, it could detrimentally impact sensitive ecosystems if left unmanaged. For these reasons, it is recommended to avoid intentional cultivation of this species and instead choose low-risk or native alternatives for landscaping or forage use.

High Risk Traits:

• Elevation range exceeds 1000 m, demonstrating environmental versatility
  
• Broad climate suitability
  
• Naturalized in regions with tropical climates
  
• Widely naturalized in the Hawaiian Islands and elsewhere
  
• Weed of lawns, golf courses and waste places
  
• Agricultural and environmental weed
  
• Hypochaeris glabra is an invasive weed
  
• Potentially allelopathic
  
• Causes stringhalt disease in horses
  
• Tolerates many soil types
  
• Reproduces by seeds and vegetatively by offsets from the crown
  
• Hybridizes with H. glabra
  
• Possibly self-compatible in certain situations (with low seed set)
  
• Reaches maturity in <1 year
  
• Seeds dispersed by wind, as a contaminant, and through external attachment to birds, other animals and possibly equipment
  
• Prolific seed production
  
• Able to resprout after fires, but controlled through cultivation

Low Risk Traits:

• Unarmed (no spines, thorns or burrs)
  
• Palatable to browsing and grazing animals
  
• Mostly self-incompatible
  
• Does not form a persistent seed bank
  
• Certain herbicides provide effective control
  
• Cultivation provides effective control