Xtremehorticulture

Check Flowers of Fruit Trees for Freeze Losses

Myer lemon (not a true lemon) fruit ready for harvest. Its orange color and round shape shows off its orange fruit heritage.


Why doesn’t my ‘Meyer’ lemon
tree produce any fruit? 

I was reminded of this question when I estimated the
fruit production this year in a Las Vegas Orchard. I use a particular variety
of pluot called ‘Flavor Supreme’ as an “indicator tree” for predicting the
probable fruit load that year. I saw no fruit developing and I saw no remnants
of flowers on these trees. I knew there was a late freeze that came through
that orchard during the spring, probably two or three weeks ago.

Tearing open a flower soon after suspected freeze damage will tell you if the fruit will fall off dead or it is alive. In this case the ovary inside is green so it shows the flower will most likely produce a fruit.

          
How did I know all that and how do I relate it back to ‘Meyer’ lemon? First of
all, recognize it only takes a 1 or 2°F difference in temperature between
having a tree loaded with fruit versus having a tree with few fruit. If this
temperature difference comes along two or three times during the spring when it’s trying to flower, then voilà, there is no fruit produced that year.

All Flowers are Sensitive to Freezing

          
The most tender parts to freezing temperatures of any fruit tree is its
flowers. When flowers are open is the time when it is most sensitive to
freezing temperatures. The tree itself is usually fine but not the flowers. If
a very light freeze occurs in the spring only once when the tree is flowering,
then fruit production is reduced. If a light freeze happens two or three times,
maybe a week apart during the spring, then the fruit is probably eliminated for
that year. However, if there is a single “hard” freeze (4 or 5 degrees below
freezing or more) as flower buds are “awake” then, most likely, all fruit will
be eliminated for that year.

          
Flowers are killed by freezing temperatures depending on their stage of
development. Flower buds during the dead of winter are very tolerant to freezing
temperatures. But in the spring, when the plant begins to “wake up” from its
winter sleep, they become more and more sensitive to freezing temperatures as
they approach opening.

Open flowers are the most
sensitive to freezing temperatures; 1°F below freezing for a very short time
kills the single chance it has for fruit. Once a flower dies, it cannot produce
fruit. If the flowering time of a fruit tree lasts three weeks, then it has a
better chance to produce fruit as more flowers continue to open. If only 5% of
the flowers are needed to produce a full load of fruit and all the flowers are
dead, there is no fruit for that year.

Leave a Comment

Your email address will not be published. Required fields are marked *