[Arid_gardener] Why are my Palo Brea Trees suddenly drying up/dieing?

[Brian Stockdell]

REQUEST ASSISTANCE with specific plant problems.
Detailed information:

~ Palo Brea Trees that are about 7 years old.
~ Description of the problem: One tree showed signs of stress a few of
months ago along with brown "ulcerations" that I have seen on many of these
trees around town, but was flowering and putting out leaves.  This week,
virtually overnight it and two other Palo Brea trees the same age had the
flowers  and leaves dry up on many to most of the branches.  The one that
was showing stress previously has a large portion of its branches drying up.
~ Location of the plant:  These trees have full sun and are planted in arid
landscape a few feet from a lawn.
~ How often you water the plant:  This trees and surrounding plants are
watered via the original drip system for 30 to 45 minutes every 3 to 7 days
depending on the season.  Two of the trees were deep soaked a couple of
times in the last month because of the one tree showing some stress.
~ Other plants in the vicinity affected:  NONE.  Other plant types under and
nearby the trees are not effected.  A 4th Palo Brea tree on the other side
of the driveway looks good.
~ Other things that might be affecting the plant : A landscape company has
recently fertilized the lawn and sprayed for weeds.  They have done this
periodically for years.
~ What do you think the problem might be and why:  Normally, I think that
they are not getting enough water, but established trees like these don't
need much water.  In fact, from what I have gathered about this tree, heavy
watering might actually be the wrong thing to do.
Thanks,
Brian