I had asked a while ago about having such a forum and the idea was shot down rather quickly. Seems we have forums for all types of things, not just plants, but on all forums photography is an important part. We only have two forms of communication here - words and photos.
I finally went off-site to a photography forum where I can ask a thousand questions and receive tons of helpful answers. Some of the photographers on that site are waaaaay out of my league price-wise, but the answers can be geared down to my price range.
For now what I do on ATP it send a Tree-mail to a member who has added a particularly good photo and ask what type of camera they are using.
You might be surprised to know that not every good photographer is willing to share that information.
Just sayin'.