Family: Amaranthaceae

Alternanthera brasiliana, commonly known as Brazilian joyweed or purple joyweed, is a fast-growing herbaceous perennial or subshrub native to Mexico, Central and South America, and the West Indies. It typically grows up to 1 meter in height and is noted for its striking reddish to purple foliage, which contributes to its popularity as an ornamental groundcover in tropical and subtropical landscapes. The leaves are ovate and vibrantly colored in shades of burgundy or magenta. The plant produces small, clustered flowers that are white to greenish-white and relatively inconspicuous.

In addition to its ornamental use, A. brasiliana is also valued in traditional medicine across Latin America and parts of Asia, where it is used to treat inflammation, wounds, and gastrointestinal ailments. While the species produces seeds, it spreads primarily through vegetative means—stem fragments that readily root in moist soil. Its tolerance of a wide range of soils and environmental conditions makes it especially resilient and capable of naturalizing in disturbed or urban areas.

Alternanthera brasiliana has been introduced to various regions beyond its native range, including the Pacific Islands, Southeast Asia, and the southeastern United States. In Australia, it is classified as an environmental weed due to its ability to form dense ground cover, outcompete native vegetation, and threaten local ecosystems. In Hawaii, it has become naturalized on the islands of Oʻahu, Maui, and Molokaʻi, though its ecological impact there is currently considered limited.

High Risk Traits:

• Broad elevation range (environmental versatility)
  
• Thrives and can spread in regions with tropical climates
  
• Naturalized Oʻahu, Maui, and Molokaʻi (Hawaiian Islands), Australia, south-eastern USA (i.e. Florida), South Africa and on some Pacific islands
  
• Aggressive and weedy in the garden
  
• An environmental weed in Australia
  
• Other Alternanthera species are invasive
  
• Can cause skin irritation (dermatitis) and asthma in sensitive individuals upon contact
  
• Shade tolerant
  
• Tolerates many soil types (not limited by substrate)
  
• Can form dense monospecific stands
  
• Reproduces by seed and vegetatively by stems and stem fragments
  
• Seeds dispersed by water, activities such as mowing and slashing, and through intentional cultivation
  
• Capable of prolific seed production
  
• Seeds may form a persistent seed bank (longevity unknown)
  
• Tolerates and resprouts after fire

Low Risk Traits:

• Unarmed (no spines, thorns, or burrs)
  
• Palatable to animals
  
• Herbicides may provide effective control