It's a little disturbing at first to see vivid photos of nature in black and white. It gives a so different atmosphere, almost anxious, but actually calmer.
"By hiding colour I don't disappear it, I emphasise it." That's true, because our brains are so used to seeing colours on plants that they immediately imagine and put colours on these photos (at least mine does :)) and maybe imagine the colours even more vivid than they are in reality.