Jujubilation

The warm spring sun shines down on rows of jujube trees in net greenhouses. We are in Kaohsiung’s Dashe District, which for six straight years has been home to the winners of the national jujube orchard management contest, conducted by the Kaohsiung District Agricultural Research and Extension Station (KDARES). We ask two-time champion Su Xincheng his secret for growing 200-gram jujubes.

Jujube professionals

The tall Su strolls through a grove of low fruit trees, undaunted by their thorns. As he prunes, he explains: “This is the third round of fruit thinning.” Small jujubes culled from the branches cover the ground, indicating that diligent fruit thinning is the key to an abundant harvest.

Su reveals that the main factor enabling jujubes to grow with thin skins and tender flesh is the proportion of nitrogen to potassium in the fertilizer. He uses sources of animal protein such as out-of-date milk and liquid eggs, seaweed extract to provide trace elements, and plant protein sources such as rice bran, to make a liquid organic fertilizer that he spreads on the roots.

The variety that won Su the championship was Kao­­hsiung No. 12 ‘Cherish.’ He says: “‘Cherish’ is low-­yielding, but each fruit can weigh 190–220 grams. They’re as large as apples, with a beautiful shape and green color, and they make ideal Lunar New Year gifts.”

In contrast to the extensive cultivation techniques practiced by his father’s generation, Su has reduced the area of his orchards but increased the harvest. This success is thanks mainly to the espalier cultivation method he developed himself. For example, each of his trees growing the Kao­hsiung No. 11 ‘Honey’ variety can produce over 400 kilograms of fruit, for an average yield of 3600 kg per 1000 square meters of land—double that of other farmers.

Fruit thinning is done to achieve the optimum leaf to fruit ratio. (photo by Jimmy Lin)

World leader in jujube varieties

Government agencies (mainly KDARES and the Fengshan Tropical Horticultural Experiment Branch of the ­Taiwan Agricultural Research Institute) have bred at least 13 jujube varieties, while since the 1960s farmers themselves have developed some 30 cultivars through selection. Taiwan is the global leader in the number of jujube vari­eties. Premium cultivars enable the fruits’ texture and size to surpass those of competitors from around the world.

Former KDARES researcher Chiou Chu-ying, who studied jujubes for 31 years, notes that most dessert jujube varieties grown worldwide were developed in Taiwan. Of the nine varieties she worked on, she is proudest of ‘Honey.’ This “explosively succulent” jujube is as juicy as watermelon and crisper than Asian pears, with a sweetness of 17–18 °Brix.

Each cultivar has its own fruiting season, so different varieties come onstream one after another to supply the export and Lunar New Year gift markets. Kao­hsiung No. 8 ‘Treasure’ is harvested from early December, whereas ‘Cherish’ hits the market in mid-January. The harvest of Tainung No. 13 ‘Shirley,’ which stores and ships well and is slated for developing export markets such as the Middle East, Canada and Japan, ends before the Lunar New Year. Meanwhile, fans of the tender, juicy ‘Honey’ need to wait until around the Lunar New Year.