Family: Cleomaceae

Origin, Description & Uses
Cleome viscosa (tickweed, wild mustard, yellow cleome) is an annual flowering herb native to the tropical and subtropical Old World and now naturalized throughout many tropical and subtropical regions worldwide (including possibly Maui). It grows 30–100 cm (1–3 ft) tall and is easily recognized by its bright yellow, four-petaled flowers, sticky glandular stems and leaves, distinctive pungent odor, and slender seed capsules. The species is commonly found along roadsides, in gardens, agricultural fields, waste areas, and other disturbed sites. Although primarily regarded as a weed, it has been used in traditional medicine in many countries, and its leaves and seeds are occasionally used as food or seasoning after appropriate preparation.

Risks & Threats
Cleome viscosa possesses several traits associated with invasive plants, including rapid growth, prolific seed production, a persistent soil seed bank, self-compatibility, and the ability to readily colonize disturbed habitats. It is a widespread weed of agriculture, gardens, roadsides, and disturbed natural areas and could detrimentally impact tropical island ecosystems by spreading into additional disturbed habitats. Although it is not known to substantially alter fire regimes, its prolific reproduction and persistence make it difficult to eradicate once established. Because this species poses an invasion risk, Plant Pono recommends choosing a low-risk or native alternative whenever one is available. Since C. viscosa may already be naturalized in parts of Hawaiʻi, avoid planting or intentionally spreading it, and manage existing populations or prevent its use in areas where it is not yet widely established to help minimize further impacts.

High Risk Traits:

• Broad climate suitability (tropical to warm temperate)
  
• Naturalized widely outside native range (including possibly Maui)
  
• Agricultural, garden, and disturbance weed; reduces crop yields
  
• Congeneric species are serious weeds
  
• Allelopathic
  
• Unpalatable to livestock
  
• Host for nematodes and plant viruses
  
• Forms dense monocultures
  
• Self-compatible (facultative autogamous)
  
• Rapid generation time (flowers in 3–4 weeks)
  
• High seed output; forms persistent seed bank (>1 yr)
  
• Dispersed by wind, water, animals, machinery, clothing, and as a contaminant
  
• Seeds sold intentionally online

Low Risk Traits:

• Not climbing or smothering
  
• Not aquatic, grass, parasitic, or spiny
  
• Not highly toxic to humans or animals
  
• Does not increase fire risk
  
• Shade intolerant
  
• Susceptible to herbicides