Introduction to Ornamental Jujube Varieties and Key Cultivation Techniques

Jujube is a traditional fruit tree species in China, planted in both the north and the south. Developing ornamental jujube for urban greening, courtyard beautification and potted display has broad prospects.

1. Suitable varieties for ornamental jujube

(1) Dongzao (winter jujube). Ripens in early November, single fruit weight 30 g, fruit round and bright red, thin skin, crisp flesh, juicy and sweet.

(2) Chengtuo jujube. Ripens in mid-September, single fruit weight 15 g, fruit shoulders have grooves and ridges, glossy and attractive, thick flesh, small stone, red color, sweet and crisp with a rich aroma.

(3) Pear jujube. Ripens in September, single fruit weight 28 g, skin light red, flesh loose, crisp and refreshing; it is currently a high-yield cultivar widely promoted in China. The selection Jinai No. 4 from it is suitable for potting.

(4) Teapot jujube. Ripens in late September, single fruit weight 11 g, the fruit has a pair of protrusions resembling a teapot spout and handle, color brown-red and glossy, flesh fine and dense, sweet, bears fruit early.

(5) Red Pearl. Ripens in late August, single fruit weight 13 g, fruit round and red, fruits set densely, flesh crisp and tender, very sweet, the crown is very easy to shape.

(6) Tailihong. Also known as Black Pearl. Fruit oblong, during the growing period the color changes from black-purple to purple-red, then to pink and then to purple-red; the flowers also change from red to yellow, making it highly valuable for ornamental retail.

(7) Chili jujube. Ripens in late September, single fruit weight 13 g, fruit shaped like a red chili pepper, fruit tip pointed and upturned, extremely attractive, flesh loose, crisp and sweet.

(8) Gourd jujube. Ripens in September, single fruit weight 9 g, fruit obovate, the upper half narrows and sinks at the waist, shaped like a treasure gourd, excellent quality.

(9) Dragon Bone jujube. Also called Dragon Whisker jujube, single fruit weight 3 g, tree form twisted and unusual, easy to shape, bears fruit early, suitable for potting.

2. Key cultivation techniques

(1) Planting requirements. Ornamental jujube can be planted along roadsides and around courtyards; the soil should be loose and fertile with high organic matter content. If the soil at the planting site is poor, it is necessary to add garden soil, pond mud or composted manure to improve the soil. Choose strong seedlings and plant them in large pits between February and March; if potted, the pot diameter should be 50-100 cm. Whether planted in the ground or in pots, apply plenty of organic fertilizer and water thoroughly to settle the roots.

(2) Shaping and pruning

For ornamental use, the natural open-center form or the small-crown stratified form is better. After planting, keep the trunk height at 30-40 cm, and develop 3-4 main branches or train tiers; the spacing between main branches is 5-15 cm; if potted ornamental jujube, dwarf and reduce it appropriately. On each main branch, select and keep 2-3 secondary main branches and an appropriate number of auxiliary branches. Pruning of ornamental jujube is mainly done in early winter and summer, chiefly thinning out water sprouts, thin and weak branches, dead branches, diseased and pest-infested branches, and branches outside the crown that disrupt the tree shape. During the peak growing season, pay attention to removing buds and thinning shoots, pinching and bending branches, to develop an attractive and distinctive crown.

3. Fertilizer and water management

Within 2 years of planting, ornamental jujube should be mainly fertilized with nitrogen, together with phosphorus and potassium fertilizers and trace elements. 10 days after planting and sprouting, apply 5-10 g of urea per tree and 2-4 kg of diluted decomposed human and livestock manure water; thereafter topdress once every 40-60 days, and the amount can increase as the crown expands; in mid-October, apply base fertilizer and wintering fertilizer, mainly organic fertilizer and phosphorus fertilizer. Adult jujube trees are topdressed once each with pre-bud fertilizer, post-bloom fertilizer and post-harvest fertilizer every year; if potted, an additional fruit-swelling fertilizer is needed, mainly organic fertilizer or compound fertilizer. The nitrogen-phosphorus-potassium ratio is 1:0.5:0.8. In addition, from April to October each year, spray the leaves with 0.2% borax, 0.2% potassium dihydrogen phosphate, 0.3% urea and rare-earth compound foliar fertilizer, which can promote fruit development and prolong leaf life. During the flowering period and fruit-swelling period, irrigate and drain promptly.

4. Flower and fruit management

Jujube is a tree species with many flowers, and the natural fruit-setting rate is below 2%. To increase the fruit-setting rate, flower and fruit management must be strengthened. First, regulate the nutrient distribution of the tree: pinch the young shoots and cut back the vegetative branches; for vigorous trees, cut the roots or girdle at the right time; second, when most fruiting branches on the whole tree have 5-6 flowers open, spray 15-20 mg/kg gibberellin once; third, spraying water during the flowering period can promote pollen germination, and spraying should generally be done in the evening or early morning when the temperature is low; in addition, spraying trace elements such as boron, zinc, manganese and rare earth, or special flower fertilizer, on the leaf surface during the flowering period can also promote fruit setting. Ornamental jujube tends to crack at fruit ripening; covering the tree disk with film (or straw) and timely irrigation can prevent a large occurrence of fruit cracking.

5. Pest and disease control

The main ones are jujube rust, jujube witches' broom, anthracnose, geometrid moths, peach fruit borer, red spider mite, scale insects and longhorn beetles. The control methods are mainly to strengthen management, enhance tree vigor, and promptly spray with high-efficiency, low-toxicity, low-residue pesticides. The specific control measures can be the same as those used in commercial cultivation.