Family: Acanthaceae

Origin, Description & Uses
White shrimp plant, also known as squirrel’s-tail (Justicia betonica), is a shrubby, herbaceous perennial native to tropical Africa and Asia. It typically grows 3–6 feet tall, with opposite, light green leaves and showy, upright flower spikes. The common name comes from the overlapping, whitish-green bracts that resemble shrimp or a squirrel’s tail, while small white or purple-veined flowers emerge from between them. In landscaping, it is sometimes grown as an ornamental for its unusual, long-lasting blooms and its ability to attract butterflies and bees. It has also been used in traditional medicine in some regions, though it is primarily valued as a garden novelty.

Risks & Threats
This species is already naturalized on Kauaʻi, Oʻahu, Molokaʻi, Lānaʻi, Maui, and Hawaiʻi Island, and it possesses several traits that are cause for concern. White shrimp plant spreads aggressively by seed and can form dense thickets along roadsides, forest edges, and disturbed areas, where it shades out and outcompetes low-growing native plants. Its ability to thrive in a range of conditions—from moist forests to drier lowlands—gives it a competitive edge in tropical island ecosystems. Because it is already widespread and poses a threat to native biodiversity, we strongly recommend choosing a low-risk or native alternative for intentional cultivation. Consider native understory plants or other non-invasive ornamentals to help protect Hawaiʻi’s unique native habitats.

High Risk Traits:

• Broad climate suitability
  
• Thrives, and spreads in regions with tropical climates
  
• Naturalized on Kauai, Oahu, Molokai, Lanai, Maui and Hawaii and elsewhere in the world
  
• An environmental weed in the Hawaiian Islands and elsewhere
  
• Other Justicia species are invasive
  
• Shade tolerant
  
• Tolerates many soil types (not substrate limited)
  
• Forms dense stands capable of excluding other vegetation
  
• Reproduces by seed
  
• Seeds dispersed in dumped garden waste and through intentional cultivation

Low Risk Traits:

• Unarmed (no spines, thorns, or burrs)
  
• Non-toxic
  
• Herbicides may provide effective control