From The Plant Encyclopedia
Gardenia is a genus of 142 species<ref name="WCSP">"WCSP". World Checklist of Selected Plant Families. http://apps.kew.org/wcsp/. Retrieved 2010. </ref> of flowering plants in the coffee family, Rubiaceae, native to the tropical and subtropical regions of Africa, southern Asia, Australasia and Oceania. Several species occur on Hawaii, where gardenias are known as nau or nānū.
They are evergreen shrubs and small trees growing to tall. The leaves are opposite or in whorls of three or four, long and 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 diameter. Flowering is from about mid-spring to mid-summer and many species are strongly scented.
- Gardenia anapetes Smith
- Gardenia brighamii H.Mann - Nānū (Hawaii)
- Gardenia buffalina (Lour.) Poir. in J.B.A.M.de Lamarck (= Genipa buffalina)
- Gardenia carinata India, Malaya.
- Gardenia cornuta (Natal Gardenia). South Africa.
- Gardenia flava (Lour.) Poir. in J.B.A.M.de Lamarck (= Genipa flava)
- Gardenia fortunei Eastern Asia.
- Gardenia gummifera India. Small tree, to 3 m high.
- Gardenia imperialis Tropical Africa. Small tree to 12 m.
- Gardenia jasminoides (Common Gardenia, Cape Jasmine or Cape Jessamine). Southern China and Japan.
- Gardenia latifolia India. Shrub or tree, 5-10 m high.
- Gardenia mannii H.St.John & Kuykend. (Hawaii)
- Gardenia remyi H.Mann (Hawaii)
- Gardenia resinifera Roth (Brilliant Gardenia, Cambi Resin Tree, or dikamali) India. Shrub or small tree, to 3 m high. (= G. lucida, Genipa resinifera)
- Gardenia resiniflua (Gummy Gardenia). South Africa.
- Gardenia rutenbergiana (Baill. ex Vatke) J.-F.Leroy (= Genipa rutenbergiana)
- Gardenia scabrella far north Queensland- used in amenities plantings in Cairns
- Gardenia spatulifolia South Africa.
- Gardenia taitensis (Tahitian Gardenia, Tiare māori). Polynesia.
- Gardenia ternifolia (Large-leaved Transvaal Gardenia). South Africa.
- Gardenia ternifolia ssp. jovis-tonantis (Welw.) Verdc. (= G. jovis-tonantis, Genipa jovis-tonantis)
- 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.
Gardenia jasminoides (syn. G. grandiflora, G. Florida) is cultivated as a house plant. This species can be difficult to grow because it originated in warm humid tropical areas. It demands high humidity to thrive and bright (not direct) light. It flourishes in acidic soils with good drainage and thrives on [68-74 F temperatures (20-23 C)] during the day and 60 F (15-16 C) in the evening. Potting soils developed especially for gardenias are available. G. jasminoides grows no larger than 18 inches in height and width when grown indoors. In climates where it can be grown outdoors, it can attain a height of 6 feet. If water hits the flowers, they will turn brown. <ref>Reader's Digest. Success with House Plants. The Reader's Digest Association, Inc. New York/Montreal. 217</ref>
In Japan and China, Gardenia jasminoides 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).
It is the national flower of Pakistan.
Crocetin is a chemical compound found in gardenia fruit (Gardenia jasminoides Ellis). In high concentrations, it has protective effects against retinal damage in vitro and in vivo.<ref>Yamauchi, M; Tsuruma, K; Imai, S; Nakanishi, T; Umigai, N; Shimazawa, M; Hara, H (2011). "Crocetin prevents retinal degeneration induced by oxidative and endoplasmic reticulum stresses via inhibition of caspase activity". European journal of pharmacology 650 (1): 110–9. doi:10.1016/j.ejphar.2010.09.081. PMID 20951131. </ref>
Starr 030523-0050 Gardenia brighamii.jpg
White Gardenia flower.jpg
Gardenia jasminoides 'Plena'
Gardenia jasminoides 'Radicans'
Gardenia psidioides flower.jpg
Gardenia volkensii flower
Gardenia volkensii flowers, foliage, fruit