Family: Cactaceae

Cereus hildmannianus subsp. uruguayanus, commonly called hedge cactus or Peruvian apple cactus, is a tall, tree-like columnar cactus native to southern South America (including Uruguay, Argentina, Brazil, and Paraguay). It grows upright with multiple branches that can reach several meters high, and produces large, nocturnal white flowers followed by fleshy, round fruits with sweet white pulp that are edible and enjoyed locally in its native range. This cactus is often used as an ornamental plant in gardens and landscapes because of its dramatic form and showy blooms, and it has also been used traditionally for food, medicinal purposes, and as a living fence because of its ease of propagation and drought tolerance. Its structure makes it useful as a sculptural element or xeriscape plant where water conservation is important.

On Kaua‘i, O‘ahu, and Maui, hedge cactus is naturalized outside cultivation, meaning it grows wild beyond intentional plantings. Although Cereus hildmannianus isn’t widely listed among Hawaii’s most problematic invasive species, its ability to establish in disturbed sites, reproduce from seeds and stem fragments, and form dense thickets in dry, open habitats indicates it can compete with native plants and other vegetation when left unmanaged. Care should be taken when planting or discarding this cactus to prevent further spread into natural areas, especially in dry forests and grasslands where it could contribute to altered plant communities.

High Risk Traits:

• Thrives in arid tropical climates
  
• Naturalized in the Hawaiian Islands, Australia, and possibly elsewhere
  
• Can invade pasture and reduce grazing potential
  
• May compete with native vegetation
  
• Other Cereus species have become invasive
  
• Spiny
  
• Unconfirmed reports of toxicity
  
• Can form dense stands
  
• Seeds dispersed by birds, frugivorous animals and intentionally by people
  
• Able to reach maturity from seed in 3-5 years
  
• May be able to spread by vegetative fragments

Low Risk Traits:

• Ornamental uses and edible fruit
  
• Self-incompatible
  
• Seeds lose viability quickly