Plant Spirit Shamanism is a book by therapist and workshop leader Ross Heaven and shamanism instructor Howard Charing that teaches how to get in touch with the spirits of plants. I have just reviewed it on Houston Shamanism Examiner.
You can find it here: http://bit.ly/aOOJDE
I really like the book, and I think you will, too. It is not another book on adventures while drinking ayahuasca (though the authors write a bit about that, too).
Plant Spirit Shamanism really talks about how to get in touch with plant spirits in many ways, and it offers exercises for doing that.
If you have read it, please leave a comment, and tell us what you liked about it (or disliked).