By Glenn I. Teves, County Extension Agent, UH College of Tropical Agriculture – Molokai
Lychee (Litchi chinensis) is native to southern China, and is a summer favorite In Hawaii. Its luscious fruit can now be purchased in cans from China, but still cannot match a juicy, right-off-the tree fruit in its prime. Then you know it’s really summer. Under ideal conditions, one lychee tree can bear over 100 pounds of fruit. One of the problems in Hawaii has been inconsistent fruiting, with most varieties bearing fruit every other year if you’re lucky.
Recent research by the USDA Agricultural Research Service in Waiakea, Hilo has developed a management system to increase fruiting of lychee. Led by Dr. Francis Zee and Dr. Stacie Matsumoto, they have developed techniques to improve fruiting and are now trying to fine tune the system in different locales on the Big Island.
Pruning immediately after harvest, three to four times a year, is an important strategy. The new growth needs to be mature by fall or those new branches will not bear fruit. Trees also need 10 days to two weeks of cool temperatures in order for these mature branches to flower and fruit in spring. I’m sure we’ve had those conditions this year. Pruning at harvest is practical and helps synchronize vegetative growth of trees, resulting in more uniform flowering and fruiting.
Two commercially important lychee cultivars imported from China include ‘Kwai Mi’ (cinnamon flavor) and ‘Hak Ip’ (black leaf). Kaimana is a Hak Ip seedling selected by Dr. Richard Hamilton of UH Manoa and released in 1982. Kaimana now dominates lychee production in Hawaii due to its large fruit, twice as large as Kwai Mi, and has an annual fruiting habit. Kaimana is usually ready to harvest from May through July.
Having a marked difference between night and day temperatures makes for a better fruit set, and lychee is one of those fruits that require a cool night and a warm day for good fruit production.