There is a central blog type site here
http://www.healinglandscapes.org/gardens/
But I have been confused myself on how the terms “healing,””meditation,” and “therapeutic” are used. ASLA seems to imply that the latter are more active and associated with a facility. I think it would depend a lot on what the staff of the place would want, and be able to use in their program. That is the place to start.
http://www.asla.org/ppn/Article.aspx?id=25294