If you are bringing in new fish and plants at the same time plants could bring something along from their previous tank. Often people soak them in a different tank or bucket for a few days.
Sometimes they use something to help cleanse them, but I do not use chemical treatments when I receive plants. Usually I know where they came from. My lfs
keeps their plants in a fishless tank separated from the other tank systems, and get lots of them from friends.
Also I haven't used either of those meds. So not sure, but it is likely to say on the bottle if it could damage plants, sensitive fish or invertebrates. If it doesn't say on the bottle, you could email the company to be sure if no one answers specifically.
What kind of plants?