Growing Epiphytes on Trees - zone 9/10 Mediteranean Climate

[Roberta]

davidg, first welcome!

Jumping in... It sounds like your climate is very similar to mine (coastal southern California USA). The coast is the big "plus factor" - it keeps winters temperate. When the temperatures go a bit lower than 10 deg C (I have a few winter nights close to freezing), it is not for many hours.

If you get driftwood that has been exposed to salt water, it may be difficult to get it clean enough for orchids. Salt is bad news. But pretty much any wood, especially hardwood, that doesn't have loose bark should work well. I think for any orchid, no matter root size, rough bark is better than smooth. I use monofilament fish line for most of my mounting. Larger things I find that I have to use something stronger, such as plastic "zip ties" or wire (the soft aluminum wire that is sold for use with Tillandsias is really easy to work with) Whatever you use, it is critically important that the plant be held in place firmly so that roots get a chance to grab the mount without movement of the plant. If the plants are already mounted, of course the problem is solved. As they grow, just tie to a larger mount. Also, if I use any sphagnum moss (for things that need to stay moist) put it on top of the roots, not under them. (If put between plant and mount, roots tend to just go into the moss)
Take a look at my website (in my signature lines) to see what I grow outside... one can get away with a lot!