Lychee Watch

Lychee trees are easy enough tree to grow, but they can be temperamental fruiters. The Pine Island Nursery Cultivar Viewer rates major cultivars on crop consistency, giving five stars to Mauritius and Kwai Mai Pink (Bosworth 3), four stars to Brewster, Emperor, Hak Ip, and Sweetheart, three to Ohia, and two to Kaimana and No Mai Tsze. Your results may vary.

What's not in question is that 2015 saw nary a lychee blossom in my groves, while 2016 finds fruit on almost every tree. Paying absolutely no attention to my recent sermon on the importance of removing fruit from young trees, I've left every one of them on.

What conditions are needed to induce a lychee tree to set fruit? According to Lychees On Line, lychees grow in 10-week cycles, consisting of a growth flush, hardening-off of the new growth, and a period of dormancy as the tree gathers energy for the next flush. The key to fruiting is to have a growth flush occur when the temperature is 68 degrees or less, causing it to develop into flower buds rather than leaves. In south Florida, chances for this are maximized by pruning back the tree in mid-July, initiating a 10-week growth cycle at the start of August. Two 10-week cycles later, a growth flush is likely to occur around the end of the year when it has its best chance to produce blooms.

Here in Southwest Florida, it's cooler in winter, enough to produce longer dormancy than just the regular portion of the 10-week growth cycle. The recommendation I've heard for our region is to prune around the end of July, avoid fertilizing after that (some even say never to use nitrogen-containing fertilizers on lychee trees), and turn off irrigation in fall and winter. This promotes extended winter dormancy. When warming weather wakes the tree up and restarts the 10-week cycle, you just need a patch of cool temperatures to occur during the flush. Some say that once the fruit forms, giving plenty of irrigation will help prevent fruit drop.

Again, your results may vary.

One way or another, our weather pattern this past winter must have been just right to trigger blooming and fruit set. But we're behind the usual schedule. At the end of February, a knowledgeable fruit man told me that there would be no lychees this year, since no blooms had yet formed. A month ago, when the first blooms were breaking, an even more knowledgeable fruit man speculated that because of the late start to the season, hot weather would cut into production and maybe even wipe out the crop. In the next sentence, however, he said he didn't really know, because such a late start is unprecedented.

All I know is that I see lychees, and they will be mighty tasty if they can reach maturity. I'm especially hopeful for my largest lychee tree, this six-foot Sweetheart planted four years ago, now loaded with its first-ever fruit. Fingers crossed.