Family: Acanthaceae

Origin, Description & Uses:
Justicia carnea, commonly known as plumeflower or flamingo flower, is native to northeastern Argentina, southern and southeastern Brazil, and Paraguay. It is a tropical shrub prized for its lush, dark green foliage and eye-catching, plume-like clusters of pink to rose-colored flowers. These blooms attract pollinators such as butterflies and hummingbirds, adding to its appeal in ornamental gardens. Well-suited to warm, humid climates and partial shade, it is commonly used in landscaping for hedges, borders, and as a colorful accent plant throughout tropical regions, including Hawaiʻi.

Risks & Threats:
In Hawaiʻi, Justicia carnea is naturalized on Maui and Hawaiʻi Island and is potentially naturalizing on Oʻahu. This species possesses traits that are cause for concern, including rapid growth, ease of vegetative spread, and the ability to escape cultivation into surrounding environments. It can form dense patches that may outcompete native understory vegetation, potentially altering habitat structure and reducing biodiversity. Because it is already spreading in parts of the state, it could detrimentally impact tropical island ecosystems if not properly managed. For these reasons, it is recommended to choose a low-risk or native alternative when considering plants for intentional cultivation, particularly near natural areas.

High Risk Traits:

• Environmental weed in Cook Islands (chokes out natives)
  
• Shade tolerant
  
• Tolerates wide range of soils
  
• Forms dense thickets
  
• Reproduces vegetatively
  
• Dispersed accidentally (garden waste) and intentionally (ornamental)
  
• Tolerates heavy pruning
  
• Congeneric weed (J. betonica)

Low Risk Traits:

• Non-toxic to humans and animals
  
• Fruits rarely produced (e.g., not in Hawaii)
  
• Slow growing
  
• Propagated mainly by cuttings