Family: Cactaceae

Origin, Description & Uses
Opuntia pubescens, commonly known as velvet bur cactus, abrojo, or chile de perro, is a low-growing cactus native to a broad region extending from Mexico through Central and South America to Venezuela and Paraguay. This species is adapted to dry tropical and subtropical climates, where it grows in open, sunny habitats. It has small cylindrical to flattened stem segments covered with fine hair-like spines and barbed glochids that give the plant a fuzzy or velvety appearance. Like many prickly pears, it is sometimes cultivated as an ornamental cactus for xeriscaping and drought-tolerant gardens, and in parts of its native range it has also been used traditionally for food and other local uses.

Risks & Threats
Although Opuntia pubescens is not currently known to be naturalized in the Hawaiian Islands, it possesses several traits that raise concern for tropical island ecosystems. This cactus can spread both by seed and vegetatively, as detached stem segments readily root and form new plants. Its barbed spines and easily detached joints can cling to animals, people, and equipment, aiding dispersal. In other regions outside its native range, including parts of South Africa and Spain, it has shown invasive tendencies and the ability to form dense, thorny patches that may displace native vegetation and hinder access by people and wildlife. Other species of Opuntia are well-known invasive weeds globally, particularly in dry environments. Because this species is adaptable, disturbance-tolerant, and difficult to handle due to its irritating spines, it could detrimentally impact Hawaii’s dry and lowland ecosystems if introduced and spread. For these reasons, choosing a low-risk or native alternative is recommended whenever suitable alternatives are available.

High Risk Traits:

• Broad native distribution and elevation range exceeds 1000 m, demonstrating environmental versatility
  
• Grows in arid tropical to subtropical climates
  
• Naturalizing in South Africa and Spain
  
• A disturbance-adapted cactus able to grow, suggesting a potential to spread into anthropogenic disturbed habitats
  
• A potential agricultural and environmental weed in South Africa
  
• Other Opuntia species are invasive weeds
  
• Armed with numerous spines
  
• Forms thickets within native range
  
• Reproduces by seeds and vegetatively within native range
  
• Spines are barbed, and joints easily become attached to passing animals or objects, facilitating dispersal
  
• Fruits and seeds, when produced, presumably dispersed by frugivorous birds or other vertebrates
  
• Limited biological and ecological information reduces accuracy of risk prediction

Low Risk Traits:

• May be restricted to full sun, or high light environments
  
• Fruit and seed production may be minimal
  
• Herbicides may be able to provide effective control, as they have on other Opuntia species