how to make old man's beard (usnea) grow?
I have some Usnea lichen (I figured this was the closest forum) from up north (I'm in North America). It is currently bonded to a small Picea glauca branch (White spruce).
It has held up OK throughout the year I've had it, but is shrinking slightly. I mist it, but I'm in a warmer area with -- importantly -- more air pollution.
As well, it is bonded to just a tiny piece of branch that I'd presume is gradually becoming "used up." I've tried to get it to affix to a freshly cut Picea abies (Norway/European spruce), but with no luck thus far. I can try some native White spruce next, if that would make a difference.
I can't control the air pollution, but any thoughts on how to otherwise optimize growing conditions for my little Old Man's Beard?
Many thanks for your input,