Family: Poaceae

Origin, Description & Uses:
Zoysia japonica, commonly known as Japanese lawngrass or Korean lawngrass, is a warm-season turfgrass native to the Russian Far East, eastern China, Korea, Japan, and other temperate parts of eastern Asia. It forms a dense, low-growing lawn with narrow to medium-width green leaves that spread by both stolons and rhizomes, creating a durable, carpet-like turf. Valued for its tolerance of heat, drought, foot traffic, and a wide range of soil conditions, it is commonly used for residential lawns, parks, golf courses, athletic fields, and erosion control. Its relatively low maintenance requirements and ability to suppress many weeds make it a popular landscaping choice in warm climates.

Risks & Threats:
Zoysia japonica is considered a low-risk species for Hawaiʻi. While it spreads steadily to form a dense turf, it is not known to aggressively invade natural areas or disrupt native ecosystems. In managed landscapes, it may slowly spread beyond intended planting areas, but this is generally easy to control through routine lawn maintenance and edging. When properly managed and planted in appropriate settings, Zoysia japonica provides an attractive, resilient groundcover with minimal environmental risk, making it a suitable choice for lawns and other maintained landscapes.

High Risk Traits:

• Broad climate and soil tolerance
  
• Forms dense, weed-suppressing sod
  
• Produces viable seed with persistent soil seed bank (>1 yr)
  
• Vegetative reproduction via stolons
  
• Dispersed via lawn clippings, intentional planting, and cattle gut passage
  
• Tolerates mowing and cultivation
  
• Hybridizes naturally with congeners

Low Risk Traits:

• Not weedy or invasive (no agricultural/environmental weed status)
  
• No spines, toxins, or allelopathy
  
• Palatable to grazers
  
• Shade intolerant and fire-resistant
  
• Low seed production (not prolific)
  
• No adaptations for wind, water, bird, or external animal dispersal
  
• Controllable with herbicides