Family: Hydrangeaceae

Origin, Description & Uses
Philadelphus karwinskyanus, commonly known as Mexican mock orange, is a flowering shrub native to southwestern Mexico through Veracruz. It is valued as an ornamental plant for its fragrant white blossoms, attractive green foliage, and ability to grow as a hedge or landscape accent. This species is often planted in gardens and residential landscapes because of its showy flowers, pleasant scent, and adaptability to a variety of growing conditions. In Hawaiʻi, it has become naturalized on Kauaʻi, Maui, and Hawaiʻi Island.

Risks & Threats
Mexican mock orange is naturalized in Hawaiʻi and possesses traits that are cause for concern in tropical island ecosystems. Like many ornamental shrubs that escape cultivation, it may spread into surrounding natural areas where it can compete with native vegetation for space, sunlight, and resources. Its ability to establish outside of cultivation raises concerns about potential impacts on native plant communities and ecosystem health over time. Because tropical islands are especially vulnerable to invasive species, this plant could detrimentally impact sensitive habitats if its spread increases. When possible, Plant Pono recommends choosing a low risk or native alternative for landscaping and ornamental planting.

High Risk Traits:

• Naturalized in Hawaii (Kauai, Maui, Hawai'i)
  
• Weed of gardens, amenity areas, and disturbance
  
• Congeneric weed (13 other Philadelphus spp. are weeds)
  
• Forms dense thickets
  
• Climbing/smothering growth habit
  
• Reproduces vegetatively (stems root on contact with ground)
  
• Dispersed intentionally by people (ornamental)
  
• Tolerates pruning/mutilation

Low Risk Traits:

• No spines, thorns, or burrs
  
• No fire hazard
  
• No viable seed production (in Hawaii)