Family: Lamiaceae
Origin, Description & Uses
Leonotis nepetifolia (annual lion’s ear) is a fast-growing flowering plant native to Africa and the Indian Subcontinent. It is recognized for its tall square stems, rough aromatic leaves, and distinctive bright orange tubular flowers that form dense globe-shaped clusters along the stem. This showy species is often grown as an ornamental in tropical and subtropical gardens and is valued for attracting bees, butterflies, and other pollinators. In some regions it has also been used in traditional herbal practices and as a casual garden plant due to its drought tolerance and ability to grow in poor soils.
Risks & Threats
Annual lion’s ear is naturalized on all major Hawaiian islands, where it spreads readily in disturbed areas, roadsides, pastures, and open natural habitats. The species produces abundant seeds, grows rapidly, and can form dense stands that compete with native vegetation and alter plant communities. Because it possesses traits associated with invasive plants—including prolific reproduction, adaptability, and rapid colonization—it is considered a high-risk species that could detrimentally impact tropical island ecosystems if allowed to spread further. To help protect Hawai‘i’s unique environments, Plant Pono recommends choosing low-risk or native alternatives instead of planting annual lion’s ear.
High Risk Traits:
- Naturalized and widely introduced outside native range
- Grows in broad climates (USDA zones 8–11) and elevations (10–1000 m)
- Forms dense thickets that displace native plants
- Acts as a weed in agriculture (cattle grazing areas), gardens, and disturbed sites
- Congeneric species are weeds
- Unpalatable to grazing animals
- Can create fire hazard (dry, dense biomass)
- Produces viable seed; self-compatible (autogamy)
- Annual, matures in ≤1 year
- Seeds dispersed by water and possibly machinery
- Intentional human dispersal (ornamental use)
- Propagules may contaminate produce (dried flower arrangements)
- Persistent seed bank (>1 year dormancy)
Low Risk Traits:
- No spines, thorns, or burrs
- No evidence of allelopathy, parasitism, toxicity (animals or humans), or allergenicity
- No vegetative fragmentation
- Not bird-dispersed or adapted for wind dispersal
- Controlled manually; no evidence of herbicide resistance
