Q. We have an
apricot tree about 5 years old. It’s
always seemed happy but this year it leafed out beautifully then last week
started losing it’s healthy green leaves on one side. Apricots are on the tree, but not developed
yet. Now half the branches on that one side are leafless.
A. I looked at the picture and it looks like a watering
problem; not enough water getting to the upper limbs and causing drought and leaf
drop. Drought occurs first on the hottest side, the sides facing the sun. If
you remember, we had a hot spell just before the weather cooled off again.
See if the tree is still alive
Go to
your tree and bend the smallest branches to see if they are still supple. For
most fruit trees, if this problem is temporary they will be supple and bend
easily without breaking. If this is the case, expect the tree to produce more
leaves and branches after a couple of weeks if it is given water.
Following the KISS rationale, we can
eliminate the less likely disease problems, a weed killer spray drifting toward
the tree, fertilizer misapplications and the like.
Now, the
cause of the drought. Water shortage to these limbs could result from not
enough water applied to the tree or in the right areas, or damage to the trunk
or limbs by boring insects tunneling through the trunk and limbs and
interrupting the flow of water. If sap is not seen on the trunk or branches or
the bark is not peeling off, then we can also probably eliminate borers.
Q. When is the best time
to check fruit trees for borers?
A. The day after it rains.
Leaf
browning and dropping from borer damage usually happens around June or July
when it gets hot. But inspect the trunk and limbs anyway for signs of borers.
Water, Water Everywhere
That
leaves us with irrigation, which is the most likely reason particularly because
of the unusual weather. A five-year old tree should be pretty big so its water
needs are also large unless you have purposely kept it smaller through pruning.
A five-year old tree probably needs around 25 to 30 gallons of water each time
it is irrigated. This water should be applied to as much area under the canopy
as possible.
How Many Emitters?
The
minimum number of emitters needed for a five-year old tree is four; each
located about 12 to 18 inches from the trunk in a square pattern surrounding
it. Six emitters arranged in a circle 18 inches from the trunk would be even
better. Apply the water long enough so it penetrates to about 18 inches deep. I
don’t know how many minutes this would be because each irrigation system is
different. But keep the number of minutes the same as before and increase the
size of the drip emitters instead if the water is not deep enough.
Giving the Tree the Shaft
To judge
if you applied enough water, use a long steel rod, like a three-foot length of
rebar, and push it into the wet soil after an irrigation. Do this in about
three or four locations to get an average irrigation depth.
This
time of year, water about Three times a week if the soil is covered in woodchips. A
thick layer of mulch on top of the wet soil usually saves one or possibly two
days between irrigations. In June, water three times a week when it starts to
get hot. If you aren’t sure when to irrigate, use a soil moisture meter like
those for houseplants, to measure if the soil is dry enough to water again. Don’t
trust the surface of the soil to tell you. Push the tip in the soil about 4 to
6 inches deep to get a measurement.
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