Family: Acanthaceae

Origin, Description & Uses:
Justicia spicigera, commonly known as Mexican indigo or mohintli, is native to regions from Mexico through northwestern Colombia and parts of the Caribbean, including the Bahamas and Hispaniola. This attractive, fast-growing shrub is valued for its bright orange tubular flowers that attract pollinators such as butterflies and hummingbirds. It typically grows 3–6 feet tall, with soft green foliage and a somewhat sprawling habit. Traditionally, it has been used as a natural dye plant—producing blue and purple hues—and in herbal teas and folk medicine. Because of its ornamental appeal and cultural uses, it is sometimes cultivated in tropical and subtropical gardens.

Risks & Threats:
In Hawai‘i, Justicia spicigera is naturalized on Kaua‘i, O‘ahu, Moloka‘i, Maui, and Hawai‘i Island. It possesses traits that are cause for concern, including rapid growth, ease of vegetative spread, and the ability to thrive in a range of environmental conditions. These characteristics can allow it to escape cultivation and form dense stands that compete with native vegetation, potentially altering habitat structure and ecosystem processes. Due to these risks, this species could detrimentally impact tropical island ecosystems if its spread continues unchecked. It is recommended to choose a low-risk or native alternative for landscaping or cultivation to help protect Hawai‘i’s unique natural environments.

High Risk Traits:

• Broad climate tolerance (USDA zones 8a–11)
  
• Naturalized in Hawaii & Texas
  
• Shade tolerant & wide soil tolerance
  
• Vegetative reproduction (nodes root)
  
• Congeneric weeds exist
  
• Resprouts after freeze

Low Risk Traits:

• No spines, thorns, or burrs
  
• Non-toxic (used medicinally)
  
• No fire hazard
  
• Not a documented agricultural/environmental weed
  
• No prolific seed production or persistent seed bank
  
• No water, bird, or gut dispersal