Family: Asteraceae

Origin, Description & Uses
Praxelis clematidea (praxelis) is a fast-growing herbaceous plant in the sunflower family native to South America, ranging from Peru and Brazil to northern Argentina. It produces clusters of small lavender to bluish-purple flowers and soft, hairy leaves, giving it an appearance somewhat similar to mistflower or ageratum. Praxelis is sometimes unintentionally spread through the ornamental plant trade, contaminated soil, or as a hitchhiker in nursery materials and equipment. In some regions it has also been observed along roadsides, disturbed areas, pastures, and agricultural lands.

Risks & Threats
Although Praxelis clematidea is not currently known to be naturalized in the Hawaiian Islands, it possesses several traits that are cause for concern. This species grows rapidly, produces abundant wind-dispersed seeds, and can quickly colonize disturbed habitats, roadsides, agricultural areas, and natural ecosystems. In tropical and subtropical regions where it has become established outside its native range, praxelis has demonstrated the ability to form dense stands that compete with native vegetation and reduce biodiversity. Its adaptability and aggressive growth habit could detrimentally impact tropical island ecosystems if introduced and allowed to spread in Hawaiʻi.

High Risk Traits:

• Broad climate suitability (tropical/subtropical, wide rainfall/elevation, some frost tolerance)
  
• Naturalized outside native range (Australia, China, Hong Kong, Taiwan, PNG)
  
• Agricultural weed (sugarcane, bananas, pastures)
  
• Environmental weed (forms dense monospecific stands)
  
• Allelopathic (inhibits other plants)
  
• Tolerates wide soil conditions
  
• Tolerates partial shade
  
• Forms dense thickets
  
• Produces viable seed
  
• Vegetative reproduction (rooting from branches)
  
• Minimum generative time: 1 year
  
• Prolific seed production (hundreds per plant)
  
• Multiple dispersal vectors (wind, water, vehicles, animals, clothing, produce contaminant)
  
• Benefits from fire and disturbance
  
• Potentially toxic to livestock and humans

Low Risk Traits:

• No spines, thorns, or burrs