What's wrong with the native soil that made you think it needed amending? How does that bed drain? I would first suspect that the fertilizer might be the problem....triple 10 can be 'hot', so to speak, and capable of causing fertilizer burn when applied too close to roots, in an excess amount, and/or tossed in fist fulls instead of lightly broadcast.

It's really not recommended that woody plants be fertilized upon planting, anyway. Especially with a fast acting fertilizer.

This area was originally just a dumping ground from the builder of this home. It was mostly dirt (rocks, silt) and broken up concrete. I got up most of the large clumps of concrete before adding dirt and planting. All the plants that the builder had here died, I figured from lack of nutrients. The bed is slightly sloped down away from the house. The two nursery's that I visited both suggested to fertilize when planting.