Though the first jujube trees grown were in Syria, Chinese records show that the jujube has been cultivated in China for 4,000 years. Most locations with warm long summers can support growth of these fruit trees. The jujube is a medium size tree, up to 25 or more feet, with glossy green, deciduous foliage. It thrives best in warm, dry climates; Fruit is generally dark brown when ripe, oval in shape, 1 to 2 inches diameter, with a single stone. Fruit will dry if left on tree, similar to figs. Skin is smooth and thin until drying of fruit occurs, then becomes wrinkled. Pulp is dryer than in most fruits.
The Chinese Jujube is a very versatile tree, yet underused. The wood is strong, durable and used for making musical instruments and crafts. Birds, horses, cattle, sheep and goats eat the fruit. The blossoms secrete copious nectar, which makes a good tasting honey. The fruit and leaves are made into a tea for sore throats. Dried seeds contain spinosin, which is a hypnotic and used for insomnia.
Given adequate heat and sun, the trees will thrive without any special care. Any location with full sun and well-drained soil will support growth of jujubes. The Chinese Jujube should not be planted in the shade of other trees. They will often fruit in the first year. They are also tolerant of high salinity, alkalinity, drought, temperatures below freezing, root exposure from erosion or roots being deeply covered by blowing sand. The Chinese Jujube is self-fertile so only one tree is needed for fruit-set. Whip-grafting can be done from one year old, immature stock.
Harvesting and Seed Production
The green fruits will not ripen after picking so it is best to wait until the fruits begin to turn yellow. They are fully ripe when brown or red and begin to shrink and wrinkle while still on the tree. The seeds are smaller than a date seed and do not always grow true to the parent tree. Seeds should be cleaned of flesh, dried under household conditions and can be stored indefinitely. Before planting, the hard shell of the seed coat should be cracked to hasten germination. Most Chinese Jujube cultivars in the U.S. are grafted or budded onto a thorny rootstalk which produces many suckers from the roots.
Pests and Diseases
Very few pests or blights affect the Chinese Jujube with a minor exception of the Caribbean fruit fly which will attack the fruit. A very serious virus, “broom”, has infected areas of China and Korea necessitating care when purchasing stock from those countries. The Chinese Jujube’s tendency to send up suckers from their roots can be controlled by heavy mulching, mowing or hoeing.
Cooking and Nutrition
Chinese Jujubes can be eaten when they reach the brown stage on the tree as the sugar content increases as it turns color. It can also be eaten before it is fully ripened, when the pulp is still crisp. It can be eaten in many forms, as a fresh fruit (including the peel), sun-dried or preserved as jelly or jam. Compared to the nutrients in an apple, the Chinese Jujube has five times as much phosphorus, twice as much potassium and ten times as much ascorbic acid.