By Mengmeng Gu, Ph D and Qiansheng Li, Ph D
Plants with Potential II: Jujube
JUJUBE, ZIZIPHUS JUJUBA, is a spe-
cies of Ziziphus in family Rhamnaceae. The other common names are red date, and Chinese date. It originated in China and has been cultivated for more than 4,000 years, as records show in the Book of Songs, the famous collection of Chinese poetry from the 10th century BC. Today there are over 800 cultivars and is one of the world’s major fruit crops. It is widely cultivated in India, Russia, the Middle East, southern Europe, and the southern United States, but mostly in China. In 2017, the total production in China was 8.52 million tons, which accounts for 97 percent of global production (8.77 million tons). Jujube was carried to the United States in 1837 from Europe, but the improved Chinese cultivars were firstly introduced by the USDA plant explorer Frank Meyer in 1908. Jujube can be grown in USDA plant Zone 6 to 9. In the United States, jujube is primarily grown in home gardens, but a few small hectare commercial plantings primarily serve niche markets in California.
WHY GROW THE JUJUBE
One of the outstanding qualities of the jujube tree is its tolerance of drought, but it is important to water immediately and frequently after planting until the trees established. Fruit splitting/cracking could be a problem from excessive amount of rainfall during fruit ripening stage. Peach moth (Carposina nipponensis) may cause damage to fruits, but its occurrence is rare. No other pests or diseases are of major concern in the U.S.
GROWING THE JUJUBE
Jujube is a small tree with strong, hard wood which grows up to 10m (30 feet) tall, depending on location. For fruit production, the tree height is usually controlled under 2.5m (8.2 feet). Planting space usually is 2-4m (6 to 12 feet). Training and pruning are important to
TNLA Green November/December 2018
develop and maintain good tree shape for high yield and top quality fruits. Both training and pruning are regular practices for fruit production. Annual training and pruning develop a strong tree framework that will support fruit production. Proper tree training also opens up the canopy to maximize light penetration, which is essential for strong flower bud development and optimal fruit set, flavor, and quality. An open center system to keep 3-4 main branches at 80-100 cm (30~40 inches), each main branch keeps 2-4 secondary shoots. Jujube could be easily grown in medium moist, well-drained soils under full sun conditions. Jujube plants tolerate alkaline soils. Mature plants also have some tolerance for drought, but perform best with regular and consistent moisture. An annual precipitation of 400-600 mm (15-24 inches) during the growing season is sufficient for good fruit set and fruit quality.
Fig.1: Some cultivars (e.g. ‘Li’, ‘Chico’, ‘Redland’ and ‘Sherwood’) have big fruits. Fig. 2: Fruits of different jujube cultivars. Fig. 3: Jujube plants flower and fruit on the current year growth. Fig. 4: Jujube plants as a thorny hedge at Washington-on-the-Brazos State Historic Site.