Family: Rutaceae

Citrus × microcarpa (calamondin, kalamansi) is a small, attractive citrus tree thought to have originated in Southeast Asia and widely cultivated across tropical and subtropical regions. It typically grows as a compact shrub or small tree with glossy green leaves, fragrant white flowers, and abundant small, round orange fruits. The fruit is very tart, with a flavor similar to lime, and is especially popular in Filipino and Southeast Asian cuisine for marinades, dipping sauces, beverages, and preserves. Calamondin is also commonly grown as an ornamental or patio plant due to its tidy growth habit, showy fruit, and ability to thrive in containers.

In Hawaiʻi, calamondin is primarily grown in home gardens and landscapes and is not currently considered a major invasive threat. However, like other citrus species, it can occasionally spread from cultivation via seeds dispersed by people or animals. Its greatest risks are indirect, as citrus trees can host agricultural pests and diseases such as citrus greening (huanglongbing) and fruit flies, which threaten both backyard and commercial citrus. Responsible planting, regular monitoring for pests, and proper disposal of fruit can help minimize these risks while allowing gardeners to enjoy this useful and ornamental tree.

High Risk Traits:

• Native to tropical/subtropical climates
  
• Widely introduced globally
  
• Produces spines (herbivory deterrent)
  
• Host for pests/pathogens
  
• Tolerates diverse soils
  
• Produces viable seeds
  
• Self-compatible/apomictic
  
• Can produce many seeds (>9,000/m²)
  
• Seeds spread intentionally and as produce contaminant

Low Risk Traits:

• Not naturalized where grown
  
• Not a weed in any category (garden, agricultural, environmental)
  
• Not allelopathic, parasitic, or toxic
  
• Not shade-tolerant
  
• No vegetative reproduction
  
• Unlikely to disperse via wind, water, or animals
  
• No persistent seed bank