Q. Have you seen a reduction in fruit
of plums, and pluots this year? My trees are 3 to 5 years old, and I did not see many
flowers on them this spring. Not a lack of pollination, but a lack of flowers!
This year the trees have anywhere from 5 to 20 fruit and last year they were
easily over 100.
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| Apricots, peaches and plums had a poor fruit set on some trees. Watch for freezing temps in the spring when they are flowering and learn about alternate bearing fruit trees. |
A.
Yes, I have seen a reduction in the amount of fruit produced this year in some
varieties and types of fruit trees. If little fruit is produced but the tree
flowered, it can be for many different reasons such as a quick freeze before
sunrise when the tree is flowering, wind, not enough pollinators like honeybees
and others.
But you nailed it. The first question to ask
yourself when there’s no fruit is, “Did it flower?” You told me your trees didn’t
flower. Without flowering it’s impossible for a fruit tree to produce fruit. Good
job!
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| Apricot flowers are seen on short shoots called spurs. Dont break them or they will never grow back. No flowers produced, then no fruit either. |
A lack of flowering this year, yet the
trees flowered in previous years, is very telling. It is either something you
did that contributed to its lack of flowering or something inherent to those
varieties of fruit trees. The three most common reasons for growth and no
flowers are heavy pruning, applying too much high nitrogen fertilizer and,
common to some types of fruit and nut trees, is a trait called “alternate or
biennial bearing”. Non-flower production can be for several reasons in
combination.
Reducing the size of a fruit tree by
pruning can shove it into a “younger” stage of development, particularly when
they’re only a few years old. Some fruit trees are more finicky about this than
others. These trees like to maintain a specific size relationship between their
root system and the spread of their limbs or shoots. This is called the trees “root
to shoot ratio”. When the top of the tree is pruned, the tree may favor the ratio
of roots to shoots it had before pruning. When the top is pruned back, the tree
throws all its energy into new growth at the expense of flowering. Luckily,
this interruption only lasts one season.
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| Some trees are more sensitive to pruning and producing fruit the next year than others. This Hachiya persimmon wouldnt produce fruit the following year after severe pruning. It did fruit the year after. |
The same interruption happens when high
nitrogen fertilizers (first number on the fertilizer bag) or excessive amounts
of fertilizer are applied to fruit trees. A telltale clue is its rapid spring
growth and its dark green leaves. I like to see about 18 to 24 inches of new
growth on young trees. I know we want trees to get big fast but be careful with
high nitrogen fertilizers. Both visual clues (lots of growth and dark green
leaves) are signs the tree received too much nitrogen and its fertilizer. Apply
a lesser amount of fertilizer (or even consider no fertilizer that year) that best
matches its need for both growth and fruit production.
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| When some plants are too young they will not produce flowers or fruit. Other reasons for no fruit can be applying high nitrogen fertilizers excessively, lack of bees, freezing temps when they are flowering and others. |
The third reason may be a fruit and nut
tree trait called “alternate or biennial bearing”. Some types of fruit and nut
trees can produce fruit heavily one year and then fruit lightly the next. These
trees are susceptible to cycles of abundant fruit followed by a trickle of
fruit the following year. Trees that exhibit this kind of trait should be
thinned of fruit a lot during years of high production. Heavy thinning in
abundant years reduces the trait of “alternate bearing”.