Gardenia is a genus of about 250 species of flowering plants in the family Rubiaceae, native to the tropical and subtropical regions of Africa, southern Asia, Australasia and Oceania.
The genus was named by Carl Linnaeus after Dr. Alexander Garden (1730-1791), Scottish-born American naturalist.
They are evergreen shrubs and small trees growing to 1-15 m tall. The leaves are opposite or in whorls of three or four, 5-50 cm long and 3-25 cm broad, dark green and glossy with a leathery texture. The flowers are solitary or in small clusters, white, or pale yellow, with a tubular-based corolla with 5-12 lobes (petals) from 5-12 cm diameter. Flowering is from about mid-spring to mid-summer and many species are strongly scented.Selected species
- Gardenia jasminoides (syn. G. augusta (illegitimate name); Common Gardenia, Cape Jasmine or Cape Jessamine). Southern China and Japan.
- Gardenia brighamii (Hawaiian Gardenia or Na'u). Lowland Hawaii in tropical dry forests. A shrub or small tree, 1-6 m high.
- Gardenia carinata India, Malaya.
- Gardenia cornuta (Natal Gardenia). South Africa.
- Gardenia fortunei Eastern Asia.
- Gardenia gummifera India. Small tree, to 3 m high.
- Gardenia imperialis Tropical Africa. Small tree to 12 m.
- Gardenia latifolia India. Shrub or tree, 5-10 m high.
- Gardenia manii (Na'u). Hawaii.
- Gardenia remyi (Na'u). Hawaii.
- Gardenia resinifera (syn. G. lucida; Brilliant Gardenia, Cambi resin tree, or Dikamali) India. Shrub or small tree, to 3 m high.
- Gardenia resiniflua (Gummy Gardenia). South Africa.
- Gardenia spatulifolia South Africa.
- Gardenia taitensis (Tiare Māori, Tahitian Gardenia). Polynesia.
- Gardenia ternifolia (syn. G. jovis-tonantis; Large-Leaved Transvaal Gardenia). South Africa.
- Gardenia thunbergia (White Gardenia, Forest Gardenia, or Witkatjiepiering) South Africa. Shrub or small tree, 2-5 m high.
- Gardenia tubifera (Golden Gardenia). Southeastern Asia. Small tree to 15 m high.
- Gardenia turgida India. Shrub or small tree to 4 m high, with spines.
- Gardenia volkensii (Transvaal Gardenia or Savanna Gardenia). Tropical Africa.
Cultivation and uses
Gardenia plants are prized for the strong sweet scent of their flowers, which can be very large in some species. Unfortunately, the strong scent can trigger headaches, asthma, or other reactions in sensitive individuals
Gardenias have a reputation for being difficult to grow. Because they originated in warm humid tropical areas, they demand high humidity to thrive. They flourish in acidic soils with good drainage. Potting soils developed especially for gardenias are available.
In Japan and China, Gardenia augusta is called Kuchinashi (Japanese) and Zhi zi (Chinese 梔子); the bloom is used as a yellow dye, which is used for clothes and food (including the Korean mung bean jelly called hwangpomuk).