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Gardenia augusta Merr. 1917
pronounced: gar-DEEN-ee-uh or-GUSS-tah
(Rubiaceae — the gardenia family)
common names: Gardenia, Cape Jasmine
Gardenia is a species of about 250 flowering plants native to the tropical and subtropical regions of Africa, southern Asia, Australia and Oceania. The genus was named by Linnaeus after Dr. Alexander Garden (1730–1791), a Scottish physician who emigrated to South Carolina and sent many specimens of American plants to Linnaeus. For some reason or other the Swedish botanist was reluctant to name a species after Garden, but finally yielded to pressure to do so; but, ironically, he gave his name to the Cape Jasmine, which had no connection with Dr. Garden, and was not even an American plant.
Gardenias are evergreen shrubs and small trees growing from 1-15 m in height. The leaves are opposite or in whorls of three or four, 5–50 cm long and 3–25 cm wide, dark green, glossy, with a leathery texture. The flowers are solitary or in small clusters, usually white or pale yellow, with a tubular-based corolla with anything from 5 to 12 lobes up to about 12 cm in diameter. The flowers of most gardenias have a strong, sweet scent, which can sometimes trigger headaches and asthma in susceptible people.
Probably the most popular of the gardenias is Gardenia augusta, and most commonly-grown varieties and hybrids have been developed from it. Many of these have double forms. The flowers of some species are used to perfume tea, and Chinese herbalists use other varieties to treat colds and influenza. A yellow dye is made from the fruits used for dyeing fabrics and foods, including the Korean mung bean jelly.
Gardenias prefer semi-shade – dappled light, or morning sun. They like an acidic soil enriched with compost. They do tend to leach trace elements from the soil, especially manganese and magnesium, and this will usually show up in a patterned yellowing of the leaves. If this happens, the trace elements need to be put back into the soil. The yellowing of the lower leaves, and their subsequent fall, is normal, as new growth is made at the head of the branches. Most gardeners prune their gardenias heavily, at least every second year, to prevent the plant from becoming leggy.
Gardenias are susceptible to infestations of mealy bug and white wax scale.
Photographs taken at Picnic Bay 2008, 2011, 2014
Page last updated 6th December 2016