Branch Dieback in Olive Sign of Soil Disease

The north third of the tree appears
to be healthy. If we remove this tree, what distance from the old hole is
needed for the new tree? We would a replacement tree to provide shade. We are
looking at oak, pine, ash, spruce or fir.  

Olive leaf drop and branch dieback may be a sign of verticillium wilt in olive.

A. That’s unfortunate. Hopefully the diagnosis was
correct and it is not something else that caused it. The information you
received about the disease sounds correct. This disease is present in the soil
and enters the tree via the roots.

            Olive
has very few pest problems and an excellent tree for the desert. Verticillium
wilt disease is rare in olive here but does occur. Symptoms include the death
and dieback of individual limbs for no apparent reason.

            Trees
resistant to Verticillium wilt disease and good choices for you in our desert include
live oak such as Heritage or holly oak, ornamental pear, European pear,
honeylocust, apple, crabapple and any of the conifers such as pines.

            Eucalyptus
is also resistant but a lot people do not like eucalyptus since it can be
“messy”. I would not recommend spruce or firs since they do not grow well in our
climate.

            If you
want warmth from the winter sun then conifers (pine) or any evergreen tree (such
as our southern oaks) is not a good choice for you. I would stay with
ornamental pear or honeylocust for seasonal shade, disease resistance and good
looks.

            If you
stay with Verticillium resistant trees, planting in the same general area
should not present a problem.