Family: Combretaceae

Conocarpus erectus (button mangrove), also known as buttonwood, is a small to medium-sized coastal tree native to tropical and subtropical regions of the Americas and West Africa. It is easily recognized by its leathery, oval-shaped leaves and distinctive button-like flower heads. Button mangrove is highly tolerant of salt spray, wind, drought, and poor soils, making it a popular choice for coastal landscaping, windbreaks, and erosion control. In Hawaiʻi, it has been widely planted for shoreline stabilization, shade, and ornamental use due to its hardiness and adaptability.

Despite its practical uses, Conocarpus erectus does possess traits that are cause for concern. The species is naturalized on Kauaʻi, Oʻahu, Molokaʻi, Lānaʻi, Maui, and Hawaiʻi Island, where it can spread beyond intended planting areas, particularly in coastal and lowland environments. Its ability to form dense stands may alter shoreline habitats, displace native coastal plants, and change soil and hydrological conditions. Caution is recommended when planting or managing button mangrove to ensure it will not negatively impact Hawaiʻi’s native ecosystems, and landowners are encouraged to consider low-risk or native coastal alternatives when possible.

High Risk Traits:

• Thrives in tropical climates
  
• Naturalized on Kauai, Oahu, Lanai, Maui, and Hawaii (Hawaiian Islands)
  
• Tolerates many soil types
  
• Capable of forming almost pure stands in native range
  
• Reproduces by seeds
  
• May be self-compatible (but also reported to be functionally dioecious)
  
• Seeds dispersed by water and intentionally cultivated by people
  
• Prolific seed production (at least in native range)
  
• Able to coppice and resprout after cutting or hurricane damage

Low Risk Traits:

• No reports of negative impacts where naturalized
  
• Unarmed (no spines, thorns, or burrs)
  
• Requires full sun
  
• Ornamental and landscaping uses
  
• May be functionally dioecious (but also reported to be andromonoecious and self-compatible)
  
• Not reported to spread far from planting sites (at least in terrestrial sites)