OK here is a bit is easy cheap wisdom i have learned thru the years of being a cat rescuer on top of my other things,
take tea bags and leach them out s oall you have is the bag of leeched tea. Allow to dry out completely and impregnate it with pure orange oil, eucolyptis works as well. Now place these eta bags just under the surface of the soil to your post or garden.
This works because cats do not like strong smells and citrus is the worst to them. and they will go where they are supposed to and not your plants. You can also take your orange peels and scatter them behind your couch and such to keep them from going there as well. you just need to replace those once a week.
Beauty the BP