I've never met a stamp-carrying, M. L.Arch. degree-holding, practicing
landscaper that uses Permaculture ideas full-time. It's regulated at the
state level. In Illinois you need 8 years with an existing licensed
Landscape Architecture firm before you can have your own stamp. In
Illinois, at least, it's illegal to advertise yourself as "landscape
architect" if you don't have a stamp. Other terms such as "landscape
designer" and "landscaper" are unregulated here.
Similarly, I've never met a M.S. or Ph.D. holding scientist that does
quantitative research on Permaculture. If they exist they don't publish.