"Most plants are, in the right hands." It's not exactly an answer, he's aware, but it's the truth. Magical types tend to be drawn to nature for a reason; the things he's seen people do with shit you could find in most people's gardens is something else.

He could stop there, but even when he could barely stand the man Eames has always appreciated Arthur's desire to understand things, so he'll expand a little. Looking around at the greenery and the butterflies as he hums a soft affirmation, "some of these are quite potent though. And rare, by the looks of it."