Family: Asteraceae
High Risk Traits:
- A temperate herb capable of growing in regions with tropical climates (e.g. Fiji)
- Widely introduced and naturalized, but no evidence in the Hawaiian Island to date
- A disturbance-adapted weed that impacts several crops
- An environmental weed, impacting desert tortoise habitat
- Other Sonchus species are invasive
- May contain toxic levels of nitrates
- Host of several economically important plant pests and parasites
- Shade tolerant
- Tolerates many soil types
- Forms dense patches that can exclude other vegetation
- Reproduces by seeds and vegetatively by subterranean roots
- Able to reach maturity in one growing season
- Seeds dispersed by wind, water, by adhering to animals, vehicles, other machinery, as a produce contaminant, and internally by animals
- Capable of prolific seed production
- Seeds may persist in the soil for up to 3 years
- Resistant to several herbicides
- Mechanical control measures may be ineffective at later stages of growth
Low Risk Traits:
- A temperate weed that may only be a threat at higher elevations
- Unarmed (no spines, thorns, or burrs)
- Palatable to livestock (in spite of possible nitrate toxicity)
- Largely self-incompatible
- Certain herbicides may provide effective control
