Family: Lamiaceae

Origin, Description & Uses
Rotheca myricoides, commonly known as blue butterfly bush, blue glory bower, blue wings, or Cambridge bush, is a tropical flowering shrub native to eastern and southern Africa, ranging from Eritrea to South Africa. It is valued as an ornamental for its striking sprays of blue to violet flowers with long stamens that resemble fluttering butterflies. The plant typically grows as a multi-branched shrub or small tree with glossy green leaves and an extended blooming season that attracts butterflies and other pollinators. Because of its colorful flowers and tropical appearance, it is widely planted in gardens, hedges, and landscapes in warm climates.

Risks & Threats
Rotheca myricoides is considered a high risk species for Hawaiʻi. It is potentially naturalizing on Kauaʻi and possesses traits that are cause for concern in tropical island ecosystems. The species produces abundant seeds, can spread beyond cultivation, and may establish in disturbed areas, roadsides, forest edges, and other moist habitats where it could compete with native vegetation. Escaped ornamental plants can contribute to long-term ecological impacts by altering plant communities and increasing management challenges in sensitive natural areas. Because this species may negatively impact Hawaiʻi’s ecosystems if its spread continues, Plant Pono recommends choosing a low risk or native alternative when suitable options are available. In areas where blue butterfly bush is already planted or becoming established, careful management and prevention of further spread are encouraged to help minimize additional impacts.

High Risk Traits:

• Elevation range exceeds 1000 m, demonstrating environmental versatility
  
• Grows in tropical climates
  
• Naturalizing on Kauai, Hawaiian Islands, and New Zealand
  
• Described as an aggressive plant that tends to spread and may become invasive
  
• Unpalatable to most grazing animals
  
• Potentially toxic
  
• Shade-tolerant
  
• Tolerates many soil types
  
• Reproduces by seeds and vegetatively by suckers
  
• Seeds dispersed by birds and intentionally by people
  
• Resprouts after cutting or severe pruning

Low Risk Traits:

• Unarmed (no spines, thorns or burrs)
  
• Ornamental
  
• Self-incompatible