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,

-James

Not to press my luck, but in case you're a sage on these matters, I'll toss out a few things I'm curious about. If not, or if you're busy, no worries.

1. Does the wood have to be in a certain state of decay before usnea can affix? (Side note: I put it on my living Dwarf Alberta spruce earlier in the year, wedging it in here and there whenever it would get knocked down. Months later, I noticed brown patches on said spruce. I'm not sure it's related, but could this be from the usnea?)

2. Does usnea grow at certain temperatures/times of year, and not during others?

3. I'm assuming that re: wind and pollution, the offender is sulfur dioxide, which must come in "batches?" In other words, if pollution were ever-present in equal amounts, wind might actually bring more airborne nasties in contact with the plant (a la wind chill/wind heat effects). Just curious. Also, is misting with chlorinated tap water a concern?

4. Does usnea have a sunlight preference?

Again, if this is too much, no need to reply -- these are just curiosities. Your first answer should get me on the right track, action-wise.

Thanks again,

James

3. I'm assuming that re: wind and pollution, the offender is sulfur dioxide, which must come in "batches?" In other words, if pollution were ever-present in equal amounts, wind might actually bring more airborne nasties in contact with the plant (a la wind chill/wind heat effects). Just curious. Also, is misting with chlorinated tap water a concern?
THINK THIS WAY. Wind that is blowing into your yard is coming from somewhere else. Would it not seem possible that that wind would be blowing in from an area that is not polluted?
Also is rain water chlorinated? Use distilled water. I am not too sure if R/O water is safe for lichens. I have one
lichen species but have not really monitored its growth. I really like the thalloid ones but was sad to discover that slugs LOVE tholloid lichens! Had a nice looking plant that seemed to be doing well with r/o water until it got munched out in one night of revelry by those narly gastropods!
4. Does usnea have a sunlight preference?
GOOD QUESTION. DON'T KNOW. but I would think that a northern exposure with indirect light is preferable unless you live where they occur naturally.

I'll give my usnea a few different branch options, to see which one it likes best.

I'm sorry to hear that the slugs liked your thalloid lichens even more than you do... I'm sure they appreciated it, at least. Hopefully, you can get a replacement.

Thanks again for your help and best of luck,

James