There are many epiphytes in the Pacific Northwest rain forest. However most
are lichens, mosses and ferns rather than flowering plants.

You didn't read my post very carefully. I said "higher plants" as in
Magnoliophyta. Even in Zone 5, we have epiphytic lichens.
Iris,
Central NY, Zone 5a, Sunset Zone 40
"A tree never hits an automobile except in self defense." - Woody Allen