Q. The palo verde tree in our daughter’s yard looks like
it has damage. The top has some dead branches in it. We have had to remove some
limbs because of this problem. Can it be saved?
it has damage. The top has some dead branches in it. We have had to remove some
limbs because of this problem. Can it be saved?
A. There are several different kinds of Palo Verde used
primarily in desert landscaping. All have tender new growth that can be
severely damaged when exposed to intense sunlight. It is important these trees
are pruned throughout their lives so that the tree’s canopy shades the trunk
and limbs.
primarily in desert landscaping. All have tender new growth that can be
severely damaged when exposed to intense sunlight. It is important these trees
are pruned throughout their lives so that the tree’s canopy shades the trunk
and limbs.
 |
| If desert adapted trees have limbs removed that expose the trunk or large limbs to direct sunlight and sunburn, borers can be a problem in these trees such as Palo Verde and acacia |
Pruning
them in a fashion that exposes limbs and the trunk to intense sunlight causes
damage that causes limb death that becomes visible a few years later. It’s a
progression that usually starts with bad pruning practices. This progression
begins when too much is removed from these trees. When too much is removed, the
limbs and trunk are exposed to high intensity desert sunlight.
them in a fashion that exposes limbs and the trunk to intense sunlight causes
damage that causes limb death that becomes visible a few years later. It’s a
progression that usually starts with bad pruning practices. This progression
begins when too much is removed from these trees. When too much is removed, the
limbs and trunk are exposed to high intensity desert sunlight.
 |
| Exposing the trunk and lower limbs to direct sunlight and sunburn can create future problems to trees like the Palo Verde. |
Intense,
direct sunlight on young limbs first causes a discoloration due to intense
sunlight. As this direct sunlight repeats day after day, exposed areas of limbs
and trunk facing the sun die. Water can’t through dead areas of the trunk and
limbs.
direct sunlight on young limbs first causes a discoloration due to intense
sunlight. As this direct sunlight repeats day after day, exposed areas of limbs
and trunk facing the sun die. Water can’t through dead areas of the trunk and
limbs.
Unless
this sunburn causes severe damage, the top of the tree probably looks fine. The
tree can still move water around the damaged area from roots to tree branches.
The damage could be as much is 50% of the limb and trunk area and the tree
looks fine.
this sunburn causes severe damage, the top of the tree probably looks fine. The
tree can still move water around the damaged area from roots to tree branches.
The damage could be as much is 50% of the limb and trunk area and the tree
looks fine.
 |
| This is not Palo Verde but when the trunk and limbs are exposed to intense sunlight for a long period of time, year after year, the intense sunlight can damage or even kill the living part of the tree under the sunburned area. The beginning of this damage can be very attractive to some wood boring insects which can make the damage worse. |
This
damage from sunburn attracts insects such as borers that feed on living parts
of the tree close to the damaged area. This feeding by borers causes even more
damage that reduces water movement to the limbs. Perhaps the first year or two,
trunk and limb damage goes unnoticed because the canopy looks fine.
damage from sunburn attracts insects such as borers that feed on living parts
of the tree close to the damaged area. This feeding by borers causes even more
damage that reduces water movement to the limbs. Perhaps the first year or two,
trunk and limb damage goes unnoticed because the canopy looks fine.
 |
| The first sign of sunburn is a discoloration or off-color to the trunk, limbs or even fruit on fruit trees. |
But at
some point, damage becomes severe enough that water movement from roots to the
canopy is reduced. Limbs start dying
back because the tree can’t get enough water past the damage. This usually
happens during the heat of the summer when demand for water is highest.
some point, damage becomes severe enough that water movement from roots to the
canopy is reduced. Limbs start dying
back because the tree can’t get enough water past the damage. This usually
happens during the heat of the summer when demand for water is highest.
The
homeowner now notices the limb death in the canopy. The homeowner removes dead
limbs. This exposes the tree to more intense sunlight and further damage. Tree
damage is so severe and unsightly the homeowner considers removing it. This is
the tree “death spiral”.
homeowner now notices the limb death in the canopy. The homeowner removes dead
limbs. This exposes the tree to more intense sunlight and further damage. Tree
damage is so severe and unsightly the homeowner considers removing it. This is
the tree “death spiral”.
What
to do? Damage to the tree may be already extensive. Decide whether you can live
with this damage or not. If not, have the tree removed. If you decide to keep
the tree, then encourage it to heal as quickly as possible. Contribute to this
healing by giving it enough water on a regular basis and apply fertilizer in
early spring.