Family: Malvaceae
Malachra alceifolia, commonly known as bastard okra, wild okra, or yellow leafbract, is a weedy herb or subshrub that poses a high invasion risk in tropical regions like Hawaiʻi. This plant is characterized by its stiff, irritating hairs and ability to form dense thickets in disturbed areas. It is a prolific seed producer, with seeds that remain viable in the soil for over five years, enabling long-term persistence and making eradication difficult. Its seeds are easily spread as contaminants in soil and agricultural produce, and the plant can resprout after cutting, allowing it to quickly colonize roadsides, pastures, and cultivated fields. It is documented as naturalized on Kauaʻi, Oʻahu, and Maui.
Despite being palatable to livestock and non-toxic, its negative impacts outweigh any potential benefits. Malachra alceifolia is listed as a noxious weed in Hawaiʻi and can host crop diseases, such as the Tobacco leaf curl Cuba virus. Effective management requires a persistent approach, including herbicide applications and careful monitoring to prevent re-establishment from the soil seed bank. Preventing its introduction and spread is crucial to protecting agricultural lands and native ecosystems.
Description and Dispersal:
- Woody forb that grows up to 3 feet
- Stems, unbranched, are covered in stellate hairs
- Leaves are roundish or broadly ovate, with shallow lobing
- Flowers are yellow
High Risk Traits:
- Broad tropical/subtropical climate suitability
- Naturalized beyond native range
- Agricultural and disturbance weed
- Forms dense thickets
- Annual with rapid generation time
- Persistent soil seed bank (>5 years)
- Tolerates mutilation (resprouts after cutting)
- Unintentional human-mediated dispersal
- Seed contaminant
- Irritating hairs
Low Risk Traits:
- Non-toxic to humans and animals
- Palatable to livestock
- Non-climbing growth habit
- No fire hazard
- Herbicide controllable
- Limited natural dispersal adaptations
