Family: Bignoniaceae

Origin, Description & Uses
Tecoma stans, commonly known as yellow bells, yellow trumpetbush, or esperanza, is native to tropical and subtropical regions of the Americas. It is a fast-growing shrub or small tree valued for its bright yellow, trumpet-shaped flowers that attract bees, butterflies, and hummingbirds. Because of its long flowering season, drought tolerance, and adaptability to a wide range of growing conditions, it is widely cultivated as an ornamental in tropical and subtropical landscapes. It is also used in hedges, screening, and erosion control, and has a history of use in traditional medicine in parts of its native range.

Risks & Threats
Tecoma stans is naturalized on Oʻahu and Maui and possesses traits that are cause for concern in Hawaiʻi. It produces abundant seeds, grows rapidly, and readily colonizes disturbed areas, roadsides, and open habitats, where it can form dense stands that compete with native vegetation and alter tropical island ecosystems. Its continued spread could further reduce biodiversity and increase management costs in sensitive natural areas. Where suitable, consider planting a low-risk or native alternative instead. Because this species is already established in parts of Hawaiʻi, it is especially important to manage existing plantings and avoid introducing or using it in areas where it is not yet widespread to help minimize further negative impacts.

High Risk Traits:

• Major environmental weed (Christmas Island, South Africa, French Polynesia, Brazil)
  
• Naturalized on O'ahu and Maui
  
• Naturalized widely outside native range
  
• Broad climate suitability (USDA zones 7–11, to 1500m)
  
• Widely introduced for horticulture
  
• Congeneric species are weedy
  
• Unpalatable to grazing animals
  
• Wind- and water-dispersed winged seeds
  
• Intentionally spread by people as an ornamental
  
• Tolerates a wide range of soils
  
• Resprouts after mutilation/coppicing

Low Risk Traits:

• Not an agricultural/forestry/horticultural weed
  
• No spines, thorns, or burrs
  
• Not toxic to animals or humans
  
• Requires full sun (not shade-tolerant)
  
• Self-incompatible (requires cross-pollination)
  
• No vegetative reproduction
  
• Not bird- or animal-dispersed
  
• Low seed production; no persistent seed bank