Generally it is safe as long as you don't wet a plant sitting in full sunlight. (The sun apparently does something that causes burning.) Having said that, it is ALWAYS preferable to test on a small spot first. I personally have never had any damage done to anything from Safer's insecticidal soap. But that does not mean that it might not. Read the label carefully (sorry, I don't have a container handy) and decide if you want to give it a try, after a spot check, that is.