Family: Lythraceae

Origin, Description & Uses:
Lawsonia inermis, commonly known as henna or mignonette tree, is native to northeastern tropical Africa, the Arabian Peninsula, and parts of South Asia from southern Pakistan to India. It is a small, much-branched shrub or tree that typically grows 6–20 feet tall, with smooth grayish bark, fragrant white to pinkish flowers, and small oval leaves. Henna is best known for its long history of cultural and cosmetic use—its leaves are dried and ground into a powder that produces a natural dye widely used for body art, hair coloring, and traditional ceremonies. The plant is also valued in some regions for its medicinal properties and as an ornamental due to its fragrant blooms and drought tolerance.

Risks & Threats:
Although Lawsonia inermis is not currently known to be naturalized in Hawaiʻi, it does possess traits that are cause for concern. Its ability to thrive in hot, dry environments, produce abundant seeds, and tolerate a range of soil conditions suggests it could establish outside of cultivation under suitable conditions. These characteristics raise the potential for it to spread and compete with desirable vegetation in certain habitats. Ongoing evaluation is needed to determine if this species could impact Hawaiʻi, and caution is recommended when planting to ensure it does not escape cultivation or negatively affect local ecosystems.

High Risk Traits:

• Adapted to a wide range of environmental conditions
  
• Naturalized in several locations
  
• Older plants with spine tipped branchlets
  
• Allergenic pollen
  
• Tolerates many soil conditions (and potentially able to exploit many different habitat types)
  
• Birds feed on the fruits and probably disperse the seeds
  
• Able to coppice resprout

Low Risk Traits:

• Grown for the cosmetic dye henna
  
• Ornamental value
  
• Slow growth rate (Reaches maturity in 5 or more years)
  
• Palatable to cattle and other ungulates