Jujube


 * For the chewy candy, see Jujube (confectionery).

Ziziphus zizyphus (syn. Z. jujuba, Rhamnus zizyphus; Jujube, Red Date, or Chinese Date (also hóng zǎo 红枣, dà zǎo 大枣, hēi zǎo 黑枣, zǎozi 枣子; Wade-Giles: tsao; Korean: 대추 daechu; Japanese: 棗 natsume; Gujarati: બોર boar) is a species of Ziziphus in the buckthorn family Rhamnaceae.

Its precise natural distribution is uncertain due to extensive cultivation, but is thought to be in southern Asia, between Syria, northern India, and southern and central China, and possibly also southeastern Europe though more likely introduced there.

It is a small deciduous tree or shrub reaching a height of 5-10 m, usually with thorny branches. The leaves are shiny-green, ovate-acute, 2-7 cm long and 1-3 cm broad, with three conspicuous veins at the base, and a finely toothed margin. The flowers are small, 5 mm diameter, with five inconspicuous yellowish-green petals. The fruit is an edible oval drupe 1.5-3 cm long; when immature it is smooth-green, with the consistency and taste of an apple, maturing dark red to purplish-black and eventually wrinkled, looking like a small date (hence the name Chinese Date). There is a single hard stone, similar to an olive stone.

Nomenclature
The species has a curious nomenclatural history, due to a combination of botanical naming regulations, and variations in spelling. It was first described scientifically by Carolus Linnaeus as Rhamnus zizyphus, in Species Plantarum in 1753. Later, in 1768, Philip Miller concluded it was sufficiently distinct from Rhamnus to merit separation into a new genus, in which he named it Ziziphus jujube, using Linnaeus' species name for the genus but with a probably accidental single letter spelling difference, 'i' for 'y'; for the species name he used a different name, as tautonyms (repetition of exactly the same name in the genus and species) are not permitted in botanical naming. However, because of Miller's slightly different spelling, the combination correctly using the earliest species name (from Linnaeus) with the new genus, Ziziphus zizyphus, is not a tautonym, and therefore permitted as a botanical name; this combination was made by Hermann Karsten in 1882.

Cultivation and uses
The Jujube has been cultivated for over 4,000 years for its edible fruit, and over 400 cultivars have been selected.

The tree tolerates a wide range of temperatures and rainfall, though it requires hot summers and sufficient water for acceptable fruiting. Unlike most of the other species in the genus, it tolerates fairly cold winters, surviving temperatures down to about -15°C. This enables the jujube to grow in desert habitats, provided there is access to underground water through the summer. Virtually no temperature seems to be too high in summertime.

Many jujube trees can still be seen in the central and southern regions of Israel, especially in the Arava Valley, where it is the second most common tree. A jujube tree near Ein Hatzeva in the Arava is estimated to be over 300 years old.

Medicinal use
The fruits are used in Chinese and Korean traditional medicine, where they are believed to alleviate stress. The fruit is ground to powder, with very small amounts required to promptly calm nerves and purify blood quality. The Australian drink 1-bil makes de-stressing (or relaxing) claims on the basis of its jujube ingredient.

Ziziphin, a compound in the leaves of the jujube, suppresses the ability to perceive sweet taste in humans. The fruit, being mucilaginous, is also very soothing to the throat and decoctions of jujube have often been used in pharmacy to treat sore throats.

Culinary use
The freshly harvested as well as the candied dried fruits are often eaten as a snack, or with tea. They are available either red or black (called hóng zǎo or hēi zǎo, respectively, in Chinese), the latter being smoked to enhance their flavour. In mainland China, Korea, and Taiwan, a sweetened tea syrup containing jujube fruits is available in glass jars,photo and canned jujube tea or jujube tea in the form of teabags is also available. Although not widely available, jujube juice and jujube vinegar are also produced.

In China, a wine made from jujubes called hong zao jiu (红枣酒) is also produced. Jujubes are sometimes preserved by storing in a jar filled with baijiu (Chinese liquor), which allows them to be kept fresh for a long time, especially through the winter. Such jujubes are called jiu zao (酒枣; literally "spirited jujube").

In addition, jujubes, often stoned, are a significant ingredient in a wide variety of Chinese delicacies. In Persian cuisine, the dried drupes are known as annab.

Other uses
The jujube's sweet smell is said to make teenagers fall in love, and as a result, in the Himalaya and Karakoram regions, men take a stem of sweet smelling jujube flowers with them or put it on their hats to attract the opposite sex.

In Japan, the natsume has given its name to a style of tea caddy used in the Japanese tea ceremony.

Pests and diseases
Witch's brooms, prevalent in China and Korea, is the main disease affecting jujubes, though plantings in North America currently are not affected by any pests or diseases.