Thunberg’s gardenia (Gardenia thunbergia)

Thunberg's gardenia

Features and Characteristics

Native to South Africa, Gardenia thunbergii, commonly called white gardenia, is a tropical/semi-tropical evergreen shrub that typically grows to 6-15’ tall (smaller in containers) and features glossy, elliptic to oval, conspicuously veined, green leaves and solitary, extremely fragrant, showy, mid- to late winter flowers. Each flower (to 5” across) is creamy white with a tubular corolla with 8 large spreading petal-like lobes.

Genus name honors Alexander Garden (1730-179- , Scottish physician, botanist and zoologist who settled in Charleston, South Carolina in 175

Specific epithet honors Carl Thunberg (1743-182- , botanist, naturalist and pupil/friend of Linnaeus.

Care and Maintenance

Winter hardy to USDA Zones 10-12 where it may be grown in the garden in humusy, organically rich, acidic, well-drained soils in part shade. Consider raised plantings in areas with heavy clay soil. Water plant soils consistently. Plants appreciate significant humidity year-round. In the St. Louis area, plants should be grown in pots or containers in greenhouses, conservatories or warm rooms. Plants may be taken outside in summer, but should be brought indoors in late summer/early fall for overwintering. As an indoor plant, grow this gardenia in bright light with moderate room temperatures. Water moderately, but do not allow soils to dry out. Prune as needed after flowering to shape. Fertilize as needed from March to August. Gardenias need lots of attention and are generally considered to be difficult plants to grow well.

Thunberg’s gardenia (Gardenia thunbergia) Requirements

Hardiness zone	10 - 12
Sun light	Part shade
Water	Medium
Maintenance	High

Common Problems

Watch for scale, white flies, aphids, mealybugs, thrips and spider mites. Powdery mildew, leaf spots, dieback, anthracnose, sooty mold and canker may occur. Leaves may yellow (chlorosis) if plant soils lose acidity. Buds may fall and/or leaf tips may blacken if temperatures or soil moisture fluctuate too much.

Uses

In St. Louis, this gardenia is planted in large containers as a greenhouse plant or houseplant that may be taken outdoors in warm growing season months.

Thunberg’s gardenia (Gardenia thunbergia) Details

Common name	Thunberg's gardenia
Botanical name	Gardenia thunbergia
Plant type	Broadleaf evergreen
Family	Rubiaceae
Hardiness zone	10 - 12
Water	Medium
Maintenance	High
Flower color	Creamy white
Flowering period	Seasonal bloomer
Height	6 - 15 ft.
Width	4 - 10 ft.