Hawaiian Gardenia
Rothmannia brighamii
A small tree or large shrub with glossy, dark green leaves clustered at branch tips and fragrant, star-shaped yellow flowers.
- Light
- Full sun to partial shade, requiring at least 6 hours of direct sunlight daily.
- Water
- Water deeply when the top few inches of soil feel dry. It requires moderate moisture but cannot tolerate standing water.
- Growth
- Perennial woody shrub or small tree, reaching a mature height of 10 to 20 feet with an upright, branching habit and moderate growth rate.
Care instructions
Provide full sun to partial shade, regular watering allowing the soil to dry slightly between waterings, and well-draining soil rich in organic matter. Apply a balanced, slow-release fertilizer during the active growing season.
Growing details
Sunlight
Full sun to partial shade, requiring at least 6 hours of direct sunlight daily.
Watering
Water deeply when the top few inches of soil feel dry. It requires moderate moisture but cannot tolerate standing water.
Soil
Prefers loose, well-draining sandy or loamy soils with a slightly acidic to neutral pH range of 6.0 to 7.0.
Hardiness zone
USDA zones 10 through 12, requiring frost-free conditions year-round.
Growth habit
Perennial woody shrub or small tree, reaching a mature height of 10 to 20 feet with an upright, branching habit and moderate growth rate.
Bloom season
Blooms intermittently throughout the warm months, producing star-shaped, bright yellow flowers with a notable fragrance.
Propagation
Propagated primarily through stem cuttings taken during active growth or by starting from fresh seeds.
Common pests & issues
Susceptible to common sap-sucking pests such as aphids and mealybugs, which can be managed with insecticidal soaps. Overwatering can lead to root rot.
Similar species
Other members of the Rubiaceae family, but distinguished by its endemic Hawaiian habitat, distinct yellow corolla, and specific leaf venation.