Jujube
| Ziziphus zizyphus subsp. var. | Jujube, Red Date, Chinese Date | |||||||||||||||||||||||||||||||||||||||||||||||||||||||
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Small deciduous tree with spines, grows fast, popular from S Europe to China. Serrated leaves are oval to lance-shaped serrated. Gives tiny (5mm) cream-colored flowers in late spring, which are followed by plum-like fruit (1.5-3 cm) which become dark red when ripe, and has one hard stone in it, like that of the olive.
Growth Habit: The jujube is a small, deciduous tree, growing to 40 feet tall in Florida, but smaller in size in California. The naturally drooping tree is graceful, ornamental and often thorny with branches growing in a zig-zag pattern. The wood is very hard and strong. Jujube cultivars vary in size and conformation, with some being very narrow in habit and others being more widespread. One cultivar, the So, seems to be fairly dwarfing in habit. After 30 years of growth in an average site, trees can be 30 feet tall with a crown diameter of up to 15 feet. Plants send up suckers (often with intimidating spines) from their roots, and these suckers can appear many feet from the mother plant. Currently, these root suckers must be controlled by mowing or hoeing.
Foliage: The small, ovate or oval leaves are 1-2 inches long and a shiny bright green. In the autumn, the leaves turn bright yellow before falling. There are usually two spines at the base of each leaf. Some spines may be hooked while others are long daggers. Virtually thornless cultivars are known. As the growing season commences, each node of a woody branch produces one to ten branchlets. Most of these are deciduous, falling from the plant in autumn.
Flowers: The inconspicuous, 1/5 inch diameter, white to greenish-yellow flowers are somewhat fragrant and produced in large numbers in the leaf axils. The flowering period extends over several months from late spring into summer. However, individual flowers are receptive to pollen for only one day or less. Pollination needs of the jujube are not clearly defined, but appear to be done by ants or other insects and possibly by the wind. Most jujube cultivars produce fruit without cross-pollination . The jujube is well protected from late spring frosts by delayed budding until all chance of cold weather has passed.
Fruit: The fruit is a drupe, varying from round to elongate and from cherry-size to plum-size depending on cultivar. It has a thin, edible skin surrounding whitish flesh of sweet, agreeable flavor. The single hard stone contains two seeds. The immature fruit is green in color, but as it ripens it goes through a yellow-green stage with mahogany-colored spots appearing on the skin as the fruit ripens further. The fully mature fruit is entirely red. Shortly after becoming fully red, the fruit begins to soften and wrinkle. The fruit can be eaten after it becomes wrinkled, but most people prefer them during the interval between the yellow-green stage and the full red stage. At this stage the flesh is crisp and sweet, reminiscent of an apple. Under dry conditions jujubes lose moisture, shrivel and become spongy inside. Tests in Russia indicate a very high vitamin C content. The fruit has been used medicinally for millennia by many cultures. One of its most popular uses is as a tea for sore throat
Adaptation: The jujube can withstand a wide range of temperatures; virtually no temperature seems to be too high in summertime. Winter dormancy allows it to withstand temperatures to about -28° F, yet it requires only a small amount of winter chill in order for it to set fruit. The plant revels in summer sun and heat, with the lack of either limiting fruit production more than winter cold. Yet jujubes have fruited in the Puget Sound and low Cascade regions of Washington State as well as in Pennsylvania. Fruiting of some cultivars has also been reported in northern Florida.The Indian jujube, which is more sensitive to frost, is grown in Florida, but the fruit is considered inferior. Jujube trees are not particularly suitable for container culture, but can be grown in this manner in a large container.
| Standard Cyclopedia of Horticulture |
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Zizyphus jujuba, Lam. Tree, 30-50 ft. high: branches usually prickly; young branchlets, petioles and infl. densely rusty tomentose: lvs. broadly oval or ovate to oblong, obtuse, sometimes emarginate, serrate or entire, dark green and glabrous above, tawny or nearly white-tomentose beneath, 1-3 in. long: fls. in short-stalked many-fld. axillary cymes: fr. subglobose to oblong, usually orange-red, 1/2 – 3/4 in. long, on a stalk nearly half its length. March-June. S. Asia, Afr., Austral.—Variable in shape and color of the fr.; for figures of several varieties see Hooker Jour. Bot. 1 (1834):321. The jujube is somewhat planted in Fla. and Calif., although it yet has no commercial rating as a fr.-plant. The frs. or berries are ripe in Nov. and Dec., and the plant begins to bear at 3 years from planting. The jujube fr. is used in confectionery.
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- More information about this species can be found on the genus page.
Cultivation
Tolerant of a wide range of temperatures and water, but won't give good fruit without summer heat and water during fruit development. Very drought tolerant if fruit is not important. Does well in desert with some water, can take extreme heat, down to -15°C, exceptionally -20°C, temperatures.
Location: Jujubes should be given a warm, sunny location, but are otherwise relatively undemanding. Given adequate heat and sun, the trees will thrive without any special care. They should not be planted in the shade of other trees
Soils: Jujubes tolerate many types of soils, but prefer a sandy, well-drained soils and do less well in heavy, poorly drained soil. They are able to grow in soils with high salinity or high alkalinity.
Irrigation: One of the outstanding qualities of the jujube tree are its tolerance of drought conditions. Regular watering, though, is important to assure a quality fruit crop.
Fertilization: Fertilizer requirements have not been studied, but jujubes appear to do well with little or no fertilization. Light broadcast applications of a balanced fertilizer such as 8-8-8 NPK at two-month intervals during the growing season would probably speed growth. Do not fertilize until the newly planted tree has several months to get established.
Pruning: Unpruned trees produce as well as trees that have been pruned. Extensive winter pruning, however, will keep the plants in better health and produce more easily obtainable fruit.
Planting: Jujubes should be set out 10 to 15 feet apart since they require high light intensities for good production. Upon setting out new, bare root trees, top the plant to 3 or 4 feet and remove all side branches to leave only a whip. New, stronger branches will emerge from each bud just below the point where the old branches were pruned.
Harvest: The crop ripens non-simultaneously, and fruit can be picked for several weeks from a single tree. If picked green, jujubes will not ripen. Ripe fruits may be stored at room temperature for about a week.The fruit may be eaten fresh, dried or candied. Fresh fruit is much prized by certain cultures and is easily sold in Chinese, Korean, Vietnamese, and Indian markets. Tree dried fruit stores indefinitely and may have good marketing potential as it dries on the tree without the use of a sulfur preservative.
Propagation
Most Chinese cultivars in the U.S. are grafted or budded onto a thorny rootstalk which produces many suckers from the roots. There is evidence that jujube cultivars will root on hard or soft wood cuttings. However, successes have been limited to date with this process of plant reproduction. Jujubes also can be propagated from seed, although they do not come true. Most jujube cultivars produce fruit without cross-pollination, but seeds from such self-pollination are usually not viable (such as from the Li or Lang cultivars) - Source: CRFG
Seed - best sown in a cold frame as soon as it is ripe. Stored seed requires 3 months warm then 3 months cold stratification[113]. Germination should take place in the first spring, though it might take another 12 months. Prick out the seedlings into individual pots when they are large enough to handle and grow them on in a cold frame for at least their first winter. Plant out in early summer. Root cuttings in a greenhouse in the winter[200]. Best results are achieved if a temperature of 5 - 10°c can be maintained[238]. Cuttings of mature wood of the current season's growth, November to January in a frame[238]. Division of suckers in the dormant season[174]. They can be planted out direct into their permanent positions if required.pf
Pests and diseases
No serious pests in the USA. Witch's brooms are a wide problem in China and Korea.
Cultivars
There are over 400 cultivars of the Jujube. Here are a few selections:
Early Ripening
- Li - Large, round fruit up to 70 g in mid-August. May be picked at the yellow-green stage. Tree is many-branched, yet narrow and upright. Best eaten fresh. Best first tree to have.
Mid Season
- Ed Hegard - Very similar to the Lang and Thornless.
- GA-866 - An outstandingly sweet selection out of the Chico Research program. Large, elongated fruit.
- Jin - An excellent elongated fruit. Very chewy when allowed to dry on the tree.
- Globe - A new, Chinese introduction.
- Honey Jar - Another new, Chinese introduction.
- Lang - Large, pear-shaped fruit which must be fully colored to be best eating. This fruit is best to let dry on the tree. Tree is upright and virtually spineless.
- Redlands #4 - Collected at an old homestead in Redlands, California. Very large, sweet, round fruit.
- So - A tree of most beautiful shape. At each node of the stem the branch decides to go off in a new direction. Hence, a very zig-zag branching pattern which casts a beautiful shadow in the wintertime. Tree is somewhat dwarfed.
- Sugar Cane - Small to medium fruit which can be round to elongated. Extremely sweet fruit but on a very spiny plant. The fruit is worth the spines!
- Thornless - Just as the name implies. Very few, if any spines occur. A fruit very similar to the Lang.
Late Season
- Admiral Wilkes - Collected on a South Seas expedition in the 1840s and planted on the Capitol grounds in Washington, D.C. Elongated fruit which has been the very last to ripen, generally in mid to late November.
- Chico (GI 7-62) - Fruit is round but flattened on the bottom. Looks like small apples. Excellent either fresh or dried.
- GI-1183 - Another cultivar from the Chico program. Large, sweet fruit.
- Sherwood - A seedling plant from Louisiana. The fruit is very dense and sweet. Tree is very narrow and upright with leaves that are weeping in habit.
- Silverhill - An elongated fruit which has cropped well even in northern Florida. Virtually spineless.
- Tigerstooth - Very similar to Silverhill.
- Topeka - From eastern Kansas and an excellent, late cropping fruit.
Gallery
Jujube tree
Dried red jujube fruits
References
- Standard Cyclopedia of Horticulture, by L. H. Bailey, MacMillan Co., 1963
- California Rare Fruit Growers - major source of text
- Plants for a Future - creative commons text source
- Flora: The Gardener's Bible, by Sean Hogan. Global Book Publishing, 2003. ISBN 0881926248
External links
- w:Jujube. Some of the material on this page may be from Wikipedia, under the Creative Commons license.
- Jujube QR Code (Size 50, 100, 200, 500)
