Question
I have a mature hedge of about 6 photinia in Hood River,
Oregon.  They are all  about 10 feet tall.  It has some black spot,
as all photinia seem to have in the Pacific NW, but it has never
gotten out of control.   I have never treated them either.  
However, last fall, I noticed one of the photinia had quite a few
dead leaves and some really bright orangey red leaves that were
not new growth, but close to the woody stems.  We had a really
wet winter and the whole photinia turned orange and died this
spring.  The other photinia around it look relatively healthy and
have lots of new growth but I see just a few dull red leaves here
and there (not new growth).  Could black spot do this, or could it
be something else. I am worried I might be too late to save the
hedge?!  Thanks so much, any advice would be greatly
appreciated!!


Answer
Amy,
From the description of the leaves, I do not feel that you are dealing with leafspot in this situation. The problem seems to be a vascular disease called Fireblight.
This disease attacks the vascular system that transports water and nutrients to the leaves and is very difficult to control.
The easiest way to minimize damage is to prune out the infected areas, making sure to sterilize the shears with bleach in between cuts. This will slow the spread of the disease.
Spray them with a copper fungicide in the early spring and fertilize them well to maintain maximum  health.
Good luck.
Ed Gulliksen