Family: Caryophyllaceae

Origin, Description & Uses
Stellaria media (common chickweed) is native to temperate regions of Eurasia and parts of northern and northeastern tropical Africa. It is a low-growing, fast-spreading annual herb commonly found in moist, disturbed soils, lawns, gardens, and mesic to wet forest edges from low elevations up to high-elevation sites. The plant forms dense, mat-like patches with delicate stems, small opposite leaves, and tiny white star-shaped flowers. It has been used historically as an edible green (especially in salads and cooked dishes) and as a minor medicinal herb, and it can also provide temporary ground cover in disturbed areas.

Risks & Threats
In Hawaiʻi, Stellaria media is naturalized on Mokupāpapa (Kure Atoll), Kuaihelani (Midway Atoll), Kauaʻi, Oʻahu, Molokaʻi, Lānaʻi, Maui, and Hawaiʻi Island, occurring primarily in mesic sites from about 50–3,950 m elevation. This species is naturalized, possesses traits that are cause for concern, and could detrimentally impact tropical island ecosystems due to its rapid growth, prolific seed production, and ability to form dense mats that compete with native understory plants and alter ground-level habitat structure. It can also be a persistent agricultural and landscape weed, spreading readily in disturbed areas and managed systems. Where possible, choosing low-risk or native groundcover alternatives is recommended; in areas where it is already widespread, management should focus on limiting spread into higher-quality native habitats and preventing further use or planting that could increase its negative impacts.

High Risk Traits:

• Elevation range exceeds 1000 m, demonstrating environmental versatility
  
• Broad native and introduced distribution (environmentally versatile)
  
• Widely naturalized
  
• Weed of lawns and gardens
  
• Weed of several crops
  
• Other Stellaria species are invasive
  
• Potentially allelopathic
  
• Potentially toxic to animals (through accumulation of nitrates)
  
• Alternate host of crop pathogens
  
• Shade-tolerant
  
• Tolerates many soil types
  
• Reproduces by seeds and vegetatively
  
• Self-compatible
  
• Able to reach maturity in under one year
  
• Can spread by rooting at nodes
  
• Seeds dispersed stuck to footwear, as a produce contaminant, by wind, birds and through the digestive tract of grazing animals
  
• Prolific seed production
  
• Forms a persistent seed bank

Low Risk Traits:

• Impacts to natural areas unknown or not documented
  
• Unarmed (no spines, thorns or burrs)
  
• Provides fodder for livestock (palatable despite reports of toxicity)
  
• Herbicides, mowing and fire may provide effective control