I have a south facing back yard with 3 Pyracantheas affixed to lattice on the south fence which I planted only about a year ago. Last year they looked great but for some reason they are struggling and the leaves are turning brown from the ground up. Last year I did amend the soil with steer manure but not sure what's gone wrong this year. Perhaps it just got too wet and cold here on Vancouver Island, not sure. Anybody else have similar problems?
Your Pyras are very drought hardy. I would expect to see a report such as yours from Southern California as opposed to where you are. I'm almost positive that if they weren't frozen to the ground, they will re-establish themselves. This gives you an opportunity (desired or not) to reshape the shrubs after you determine what lives and what died.
Minus 21 Celsius in November (Okanagan) and very nearly that cold (Vancouver Island) was hard on plants. Shaping Pyracantha is not a favourite task for most folks. But as you suggest, this gives an opportunity to get rid of the dead branches.
I understand your lack of interest in removing those thorny branches. I face the same thing with my bougainvillea, but by cutting one small branch at a time, then cutting that one into six inch pieces, then the next, you can easily work your way through the unpleasant job and have a relatively small pile in the trash can for recycling or trash- - whatever they do with it where you are. Have fun, and think of how nice it will look.
