They are mostly not real rocks, and the ones that are are glued securely in position. Others are flat and well nesteled in the peat (around the water bowl)
Here are two, you can use: Pothos or any Tillandsia for humid enclosures and some grey/silver types of Tillandsia are able to grow in drier enclosures. They are perfect plants since they don't need any substrate to grow, so you can put them on the cork bark, wood, branches etc. and it will grow. Just found out and going to get some of these for my P. cambridgei enclosure. Here are some examples: and really appreciate the advice !! I spent the day finishing up the wiring and trim ! In same enclosure I have forest moss(real one, not bought one), some grass from forest and ivy. All plants are growing nicely without any problems. For second arboreal enclosure for my P. cambridgei I will use forest moss and tillandsias, that bulb tillantzia looks just amazing and it will go grat with my bark backround. What kind of lightning do you use? And don't worry, I bet lot of us made mistakes with rocks I bet. You have a lot of spiders in your collection since you are short time in the hobby. I had my first one, B. smithi for a bit more than an a year now, and this year I got the other two. But I think your spiders feel right at home. 
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