The Sound Machine

From the text:

"You might say," he went on, "that a rose bush has no nervous system to feel with, no throat to cry with. You'd be right. It hasn't. Not like ours, anyway. But how do you know, Mrs Saunders"--and here he leaned far over the fence and spoke in a fierce whisper "how do you know that a rose bush doesn't feel as much pain when someone cuts its stem in two as you would feel if someone cut your wrist off with a garden shears? How do you know that? It's alive, isn't it?"