R. E. Russell Jr. wrote:
This year I used a higher priced fertilizer (27-3-4) just before the problems started.
I would call that your problem right there.
Ultra-High nitrogen can very often cause a number of more tender plants to flush out with all sorts of new growth that is very weak and dies at the drop of a hat.
The sick tree treatment will help get things back on track. Wouldn't hurt to add some Zeolite and/or Dry horticultural moasses to the ground to detow it from that high salt fertilizer. If you haven't already done so, check that the root flare is adequately exposed and aerate the root zone.