Thanks all.
Jo, I toootally meant it >.>. I was actually thinking about roots, but I wanted them twisted and hugging the bank - I was too lazy to model them in C4D/XFrog.
mHaze... the colour variation is an interesting one. There should be near-whites and dark greens in there - you can see them in the preview render (if I recall correctly), but they didn't "come out" in the render *shrug*