Family: Caprifoliaceae

Origin, Description & Uses
Lonicera japonica (Japanese honeysuckle) is a fast-growing, twining vine native to East Asia, including Japan, Korea, and parts of China. It was introduced to many regions around the world, including Hawaiʻi, as an ornamental plant valued for its fragrant, tubular white-to-yellow flowers and its ability to quickly cover fences, arbors, and slopes. In some areas it has also been used for erosion control and as a ground cover due to its vigorous growth and dense foliage.

Risks & Threats
Japanese honeysuckle is naturalized on Kauaʻi, Oʻahu, Maui, and Hawaiʻi Island, and it exhibits traits that make it a serious concern for Hawaiʻi’s ecosystems. It grows rapidly, forms dense mats, and can smother native vegetation by blocking light and outcompeting plants for space, water, and nutrients. It also spreads easily through both seeds (dispersed by birds) and vegetative rooting at stem nodes, allowing it to invade forest edges, disturbed areas, and open landscapes. Once established, it is difficult to control and can alter habitat structure and reduce native biodiversity. Because of these impacts, it is considered a high-risk species in tropical island environments. When possible, choosing a low-risk or native alternative is strongly recommended to help protect Hawaiʻi’s natural ecosystems.

High Risk Traits:

• Broad climate tolerance (zones 4A–10A; sea level to 4,000 ft)
  
• Widely cultivated and naturalized beyond native range
  
• Agricultural/forestry weed (interferes with pine regeneration)
  
• Environmental weed (smothers native plants)
  
• Congeneric species are invasive
  
• Host for crop pests (tobacco leaf curl virus, whitefly)
  
• High flammability; creates fire hazard
  
• Shade-tolerant; persists in forest understory
  
• Tolerates wide soil conditions (including salt and drought)
  
• Climbing/smothering growth habit
  
• Produces viable seed and spreads by root fragments
  
• Spread unintentionally (garden waste) and intentionally (landscaping)
  
• Bird-dispersed seeds survive gut passage
  
• Persistent seed bank (viable >3 years)
  
• Resprouts after cutting, mowing, or fire

Low Risk Traits:

• No spines, thorns, or burrs
  
• Requires cross-pollination (not self-compatible)
  
• Low seed production (especially in shade)
  
• No wind, water, or external animal dispersal