How do you stop cats peeing in your plants?

We’ve got these potted plants either side of our front door and one of them certainly looks as though it has seen better days, I’m pretty sure a neighborhood cat has decided to make it their lavatory of choice. I’ve heard that putting mothballs down can keep cats away but would they not just soak into the ground and damage the plants themselves anyway?

(Jesus Christ when did I get so fucking middle aged?)