Family: Ochnaceae
An invasive shrub that spreads from initial plantings. Like many plants native to South Africa, Ochna serrulata thrives in Hawai’i. The unusual look of mature black fruit along with persistent red sepals resembles the ears and pants of Mickey Mouse, hence the common name ‘mickey mouse plant.’ On Hawai’i Island in Manukä State Park, the mickey mouse plant has formed a thicket so dark and crowded that native plants can’t regenerate. This mesic ʻŌhiʻa dominated forest is being chocked out by many mickey mouse plants.
Mickey mouse plant is invasive in Australia as well. There it grows in a variety of climates from rainforest to riparian areas to dry forests. Birds, a significant disperser, are very attracted to the oily protein-rich fruit. Water and humans are also dispersers of Ochna seeds. Do not cultivate in Hawai’i.
Description and Dispersal:
- An erect evergreen shrub growing up to 7 feet tall
- Leaves have a wavy surface, finely toothed margins, and are green
- Leaves are spirally arranged
- Flowers are yellow, have 5 petals, and are fragrant
- Fruit appears after petal fall off, green then turning black
- Red sepals persist under the fruit
High Risk Traits:
- Naturalized in Hawaii (O'ahu, Maui and Hawai'i Island) and Australia
- Environmental weed in Australia; dominates shrub layer
- Congeneric (O. thomasiana) is invasive
- Shade tolerant (understory plant)
- Forms dense, blocking thickets
- Produces viable seed
- Reproduces vegetatively (cuttings, clippings)
- Intentionally spread by people as ornamental
- Propagules dispersed by water and birds
- Seeds survive bird gut passage
- Tolerates clipping; re-sprouts after damage
Low Risk Traits:
- No spines, thorns, or burrs
- Minimum 4+ years to maturity
- Seeds large → not wind-dispersed, produce contaminant, or unintentionally moved
- No external animal dispersal
- Low seed production; no persistent seed bank
- Well controlled by herbicides
