Family: Brassicaceae

Origin, Description & Uses
Lepidium africanum (African pepperwort) is a fast-growing herb in the mustard family native to northeastern Sudan, southern Africa, and parts of the Arabian Peninsula. It is a weedy annual or short-lived perennial with slender branching stems, small narrow leaves, and tiny white flowers that produce numerous seeds. African pepperwort is adapted to dry and disturbed environments and is often found along roadsides, pastures, gardens, coastal areas, and waste places. In some regions, species of Lepidium have been used traditionally as minor culinary herbs, forage plants, or for folk medicinal purposes, though African pepperwort is more commonly regarded as a weed than a cultivated plant. In Hawai‘i, it has become naturalized on Kaua‘i, O‘ahu, Maui, and Hawai‘i Island.

Risks & Threats
African pepperwort is considered a high-risk species because it is naturalized in Hawai‘i and possesses traits associated with invasive plants, including rapid growth, prolific seed production, and the ability to spread easily in disturbed habitats. Once established, it can form dense populations that compete with native vegetation and alter plant communities, particularly in dry and coastal ecosystems. Its tolerance for a wide range of environmental conditions increases the likelihood that it could continue spreading into sensitive natural areas. Because tropical island ecosystems are especially vulnerable to invasive species, African pepperwort could detrimentally impact native biodiversity and ecosystem function if left unmanaged. Plant Pono recommends choosing low-risk or native alternatives instead of this species for landscaping or cultivation in Hawai‘i.

High Risk Traits:

• Broad climate suitability (elevation 0–1200 m)
  
• Naturalized outside native range (New Zealand, Japan)
  
• Weed of disturbed areas, agriculture, and environmental habitats
  
• Congeneric weed (L. latifolium is highly invasive)
  
• Tolerates wide range of soil textures
  
• Produces viable seed
  
• Annual or biennial (short generation time)
  
• Propagules dispersed unintentionally (crop contaminant)
  
• Wind-dispersed seeds
  
• Seeds survive passage through animal guts
  
• Tolerates or benefits from fire (increased presence post-burn)

Low Risk Traits:

• No spines, thorns, or burrs
  
• Palatable to grazing animals (sheep select it)
  
• No evidence of toxicity to animals or humans
  
• Not shade tolerant
  
• No vegetative fragmentation
  
• No intentional dispersal by people
  
• Not dispersed by water, birds, or external animal attachment