How to Keep Your Privets From Dropping Leaves in the Winter

Leaf loss on privets on left side of fence but not on right side.

Q. I have been living at my address for 7 years and the
last two years my privets have turned brown and lost their leaves during the
months of January and February. I attached some pictures.  Last year they came back although they weren’t
as full and robust as they used to be. The Texas privets right next to them
seem to do fine throughout the winter. Why are they all of the sudden loosing
all of their leaves in the winter? What can I do to save my privets and have
them come back with full growth? 

Leaf loss on privets on left side closerup

A. There are two things going on that need to be
corrected or the others will start looking like the bad ones as well. You are
looking at a snapshot in time. The two problems are how the plants are pruned
and the depletion of the soil. I know that this is not very logical in relating
why these plants are dropping their leaves but both are influential in helping
plants keep their leaves during the winter months and does explain why they are
less hardy than the others.

No leaf loss on Texas privet on right side of fence.

Most likely these plants are pruned with a hedge shears.
And although they are being maintained as a hedge if we are not careful in a
few years the old woody growth dominates the hedge (particularly at the bottom)
and cannot support young succulent growth with lots of leaves. Hedges are
supposed to be pruned like a trapezoid with the wider base at the bottom. Or
they can be pruned individually to remove older growth (this is called renewal
pruning) and then it can be hedged. This type of pruning causes newer growth at
the bottom which supports leaves and then the plants are full from top to
bottom.

The second problem is the type of mulch I think you are
using. Rock mulch returns nothing to the soil. As plants grow and are pruned
and the prunings taken away this takes alot from the soil. Simply applying a
fertilizer is not adequate over time. The soil becomes depleted of the
“organic matter” in the soil and many of the soil processes necessary
for good plant health diminish over time to the point that the plant becomes
“sick” or unhealthy. Unhealthy plants are more prone to winter damage
than healthy plants. Healthy plants can withstand lower winter tempertures than
“sick” plants. The first sign of low temperature damage of evergreens
is the damage to leaves and stems and leaf and sometimes stem death and the
leaves fall off.

To correct these problems you need to probably remove the
rock mulch and put down first, compost and then follow it with coarse wood
mulch that will not blow into your spa/pool. Bark is not suitable, it will not
enrich the soil enough and will blow into the water. Coarse mulches such as you
get from chipping trees interlocks and does not blow easily. Furthermore it
breaks down and helps enrich the soil where bark does not. It is only
decorative.

Unfortunately I think the damaged privets may be beyond
help in the near future. It will take time for them to recover. If you want to
invest that type of time then someone will need to start pruning them properly
and renewing the soil with amendments that have been depleted. Otherwise I
would just replace the plants as they go downhill and maintain a schedule of
plant replacement over the years as the plants start to look ugly. Hope this
helps.