Family: Acanthaceae
Barleria cristata, also known as the Philippine violet or bluebell barleria, is a shrub in the Acanthaceae family that is now widespread across several of the Hawaiian Islands, including Kauaʻi, Oʻahu, Maui, Molokaʻi, and Hawaiʻi. It thrives in a broad range of conditions, tolerating shade, a variety of soil types, and elevations over 1,000 meters. It spreads both by seed—through explosive seed capsules and possibly by water or attachment to animals or humans—and vegetatively, as its branches can root when they touch the ground. Once established, it can form dense stands and resprout after pruning or cutting, making it difficult to manage.
On the upside, Barleria cristata is non-toxic and valued for its ornamental beauty and medicinal uses. Its trumpet-shaped flowers, which can be lavender, pink, or white, have made it a popular garden plant in other regions. Despite these benefits, the ecological risks in Hawaiʻi are significant: it’s considered a “disturbance weed” that can negatively affect agricultural lands and native ecosystems. Although widespread, it is not recommended for cultivation in Hawaiʻi due to its ability to spread aggressively and impact natural areas.
High Risk Traits:
- Elevation range exceeds 1000 m, demonstrating environmental versatility
- Thrives in tropical climates
- Naturalized on Kauai, Oahu, Maui, Molokai and Hawaii (Hawaiian Islands) and elsewhere
- A disturbance weed with possible impacts to agriculture and the natural environment
- Other Barleria species have become invasive
- Spinose bracts
- Shade tolerant
- Tolerates many soil types
- Can form dense stands (Hawaiian Islands)
- Seeds dispersed by explosive dehiscence of capsules, as well as secondarily by water, and possibly by attachment to people, animals or machinery
- Able to spread vegetatively by branches that root when touching the ground
- Can be spread by discarded garden clippings
- Able to resprout after cutting, pruning or fire
Low Risk Traits:
- Non-toxic
- Valued for ornamental and medicinal uses
