Clidemia hirta – Koster's Curse

Clidemia hirta - Koster's Curse, Soapbush, Soap Bush, Clidemia (flower)

Clidemia hirta - Koster's Curse, Soapbush, Soap Bush, Clidemia (fruit)

Clidemia hirta - Koster's Curse, Soapbush, Soap Bush, Clidemia (leaves)

Plant Name

Scientific Name: Clidemia hirta

Synonym: Melastoma hirtum

Common Names: Koster's Curse, Soapbush, Soap Bush, Clidemia

Plant Characteristics

Duration: Perennial, Evergreen

Growth Habit: Shrub

Hawaii Native Status: Introduced. This naturalized weed is native to Mexico and Central and South America.

Flower Color: White

Height: Up to 6 1/2 feet (2 m) tall or more

Description: The flowers are small and have 5 white, hairless petals. The flowers are followed by hairy, rounded, 1/3 inch (9 mm) long, green ripening to dark purple berries. The leaves have 5 recessed longitudinal veins, hairy, finely round-toothed margins, and are shiny, bright green to dark green, bristly hairy, opposite, broadly to narrowly egg-shaped, and deeply quilted with small, depressed, transverse veins. The plants are covered with small, needle-sharp, bristly hairs that can penetrate the skin and cause irritation, so beware of handling or walking through these plants.

Here in Hawaii, Koster's Curse is an aggressively invasive weed in sunny to shady, wet to mesic (moderately wet) pastures, forests, and forest edges at lower elevations. The plants are thicket-forming and will crowd out native plants. Birds enjoy the sweet, fleshy berries and are responsible for spreading the seeds.

Special Characteristics

Legal StatusHawaii State-listed Noxious Weed


Kingdom: Plantae – Plants
Subkingdom: Tracheobionta – Vascular plants
Superdivision: Spermatophyta – Seed plants
Division: Magnoliophyta – Flowering plants
Class: Magnoliopsida – Dicotyledons
Subclass: Rosidae
Order: Myrtales
Family: Melastomataceae – Melastome family
Genus: Clidemia D. Don – clidemia
Species: Clidemia hirta (L.) D. Don – soapbush

More About This Plant

Hawaii County Distribution Map