My uncle is a landscape architect in southwestern Florida with Grady Minor Associates, so I thought I'd visit his office while I was there. His niche, as far as I can tell, is that he hand drafts and renders - that is, the man can draw. Almost no one does this in architecture so I assume it's somewhat rare in landscape too. He uses Autocad and Photoshop aside from drawing but generally only at the back end of the design. For the most part iterations are done free hand. What I find interesting is that clients specifically request him because of the way he works - which isn't all that surprising to me but is of course counter to so much of what I learn in school.
An entire wall plastered with plans and sections on trace paper.
This rendering (about 2' x 3') took him about 20 hours - about the same as a computer if not less.