Gardenia jasminoides (also known as Gardenia augusta) is a fragrant flowering shrub with attractive shiny green leaves and produces fragrant white summer flowers. It is a widely cultivated garden and houseplant and can be grown in pots or outdoors in the ground as a fragrant hedge. Many varieties are now available – there those that are compact and low-growing, flowers are available in both single and double forms, as well as, plants with variegated and non-variegated leaves.
Commonly known as the cape jasmine or garden gardenia, Gardenia jasminoides is a temperate plant that is native to southern China, Japan, Taiwan and possibly also Sri Lanka. In the tropicals, it is reported to do better at altitudes of 400—1200 m. In Singapore’s hot and humid tropical climate, I noticed it prefers to be grown in a semi-shaded location outdoors. Direct sunshine in the tropics is a little too harsh for this shrub. Heat- and water-stressed plants can shed their leaves or their foliage can sometimes taken on an unhealthy yellow colour.
In the tropical lowlands, this shrub flowers sporadically with a few blossoms each time. It thrives best in fertile and properly drained soil that is near neutral pH value. Do not let the soil dry out and the root zone should be kept moist at all times. Note that the flowers of this shrub are easily damaged by heavy tropical rains and hence it is better to try grow Gardenia jasminoides in a container which can be easily moved around during the rainy season. Interestingly, this shrub tend to flower during the rainy season and that is not surprising, as that is when the weather is much cooler. Bring a potted flowering specimen under shelter to appreciate the flowers so that the flowers don’t get damaged.
When not in flower, the dark leaves of this plant are glossy and makes an ideal foliage plant. This is achievable only when the plant is grown under semi-shade. There is a variegated version and one can see a colony being grown in HortPark’s Floral Walk. The attractive leaves of this cultivar are splashed with random swirls and patches of yellow. Unforunately, I faced much trouble trying to find and admire the flowers produced by the variegated version Gardenia jasminoides. The white flowers do not contrast well with the variegated folige backdrop.
Not commonly produced here in Singapore, the fruits of the cape jasmine are used in China and Japan for colouring food yellow. Some extracts are commercially available in Japan and they are used to colour boiled beans, fish eggs, hot cakes, liquor, sweets, ices, noodles, candies and imitation crab. The colouring matter in the fruits contains a glycoside, which is identical with the compound called crocetin found in saffron (Crocus sativus L.). The colouring matter is a type of carotenoid pigment. However, more research is needed to prove the harmless character of the dye. The dye is also used to colour textiles yellow or scarlet.
Do you know that the fragrant flowers yield fragrant essential oils and are used in perfumery? In China, they are used for flavouring tea like the common jasmine (Jasminum sambac). Several parts of the plant are used medicinally. The roots are used against headache, dyspepsia, nervous disorders and fever while the leaves are applied in febrifugous poultices. Besides yielding colouring matter, fruits are also used against jaundice and diseases of kidneys and lungs. The seeds contain starch and an oil which is principally composed of palmatic, oleic and linoleic acid.