From Lychees Online
by Krystal Folino and Bill Mee
Tips on Getting
Your Lychee Tree to Produce Fruit
Lychee trees grow in recurrent cycles of growth followed by periods
of dormancy. Typically, a South Florida lychee tree will experience 4 -
6 annual growth flushes depending on the age and size of a tree. The
trick is to have the tree enter the cooler months in a state of
dormancy so that the next wave of emerging buds develop into bloom
spikes, providing that the temperatures are at or below 68 degrees F
(20 degrees C).
Now that we have identified one reason why
many lychee trees irregularly produce fruit in South Florida, we need
to outline a possible solution to this problem. No amount of possible
solutions can overcome a winter with daytime temperatures in the 80s
and nocturnal temperatures in the 70s, but usually during most Florida
winters we will experience one or more cold fronts moving in from the
northwest.
The solution begins many months in advance of the
flowering season, which typically runs from late December through
January. The end, in this case, is flower bud formation and the means
are pruning. To visualize this process you need to plot out a linear
calendar timeline showing all of the weeks from July 1 though the end
of January. Ideally, we want our trees to be ending a cycle of dormancy
sometime between the end of December and the middle of January.
A
typical cycle encompasses a period of approximately 10 weeks where the
first five weeks involve a new growth flush forming and hardening off.
"Hardening off" is defined as the leaves going from a delicate light
green state to a tougher dark green condition. During the second 5
weeks of this cycle the leaves simply sit there and collect sunlight
and do their photosynthesis thing. If you plot backwards from January 1
you will identify the end of July as the starting point of the two 10
week cycles.
| Months |
| J |
J |
J |
J |
A |
A |
A |
A |
S |
S |
S |
S |
O |
O |
O |
O |
N |
N |
N |
N |
D |
D |
D |
D |
J |
J |
J |
J |
| Pr |
fl |
fl |
fl |
fl |
fl |
dr |
dr |
dr |
dr |
dr |
fl |
fl |
fl |
fl |
fl |
dr |
dr |
dr |
dr |
dr |
bl |
bl |
bl |
bl |
J = July, A = August, S = September, O = October, N= November, D =
December, J = Jannuary
Pr = Prune, fl = flush, dr = dormant, bl = bloom
Basically,
you have to synchronize your tree(s) to a known starting point so that
they will be at their most susceptible point when conditions will be
optimum for bloom formation around the start of the New Year. What this
means is that if you prune your trees around the middle of July, just
after the harvest (if you had one) they will just be beginning to flush
out at the end of July to the beginning of August. This is one of the
reasons why post harvest pruning tends to lead to higher crop yields.
Not
to despair completely if your tree is aggressively flushing out as we
speak, which means you can forget about fruit. It is possible to prune
off part of the new growth thereby inducing lateral bud formation in
about 10 days. If a cold front moves in within the intervening 2 weeks
you may still have a chance to get flowering and maybe fruit.
by Bill Mee and Krystal Folino - Lychees Online
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