Drought?

Definitly not drought. Nor is it too dry.

I feel that unpruned (as in un-thinned) kerrias tend to dump their oldest branches...think that might the the issue? Or are young ones and old ones dying?

Keep us posted.
Take care,
Grant

Ah, Grant, no that is not the problem.

I thin it every fall and this spring, I removed all the browning branches. young branches are dying. This is not part of the normal growth process.

Hmmm...thanks for replying. If it's not just old tired wood dying, then hopefully you and/or someone will figure it out. I sure hope so. Good luck and keep us posted.

Take care,
Grant

For failing plants with no known obvious pest or disease issues - kerria is generally considered a pretty trouble-free shrub - there are several factors one should consider: watering issues - too much or not enough; changes in soil levels, compaction or drainage or activity in the area that could damage roots; chemical injury from pesticides or other contaminates. If you are absolutely certain none of these apply, then you do indeed have a mystery on your hands. Perhaps taking in a sample to a nursery or your local extension office for a problem diagnosis would shed more light.

That covers it very nicely.