The black is not as noticeable as white, and their presence will make the pots an uncomfortable place to lounge. You may have some luck by soaking popsicle sticks in a nasty smelling repellant, then sticking them in the soil where cats congregate. Not only will the cat not want to pick it's way through the popsicle stick obstacle course, it won't like what it's smelling. You can use anything from commercial repellants to predator urine to scent the sticks. There are also some items out there that you can attach directly to plants.
Many people have success using commercial repellents in their garden.
However, you may find that these are all you need to keep cats at bay. It's called the Reppers Repellent Kit . Please don't put anything in it but water, because to do so might harm the cat's eyes. As a rule, cats don't like to get wet. While I have not used a Super Soaker, I have turned my garden hose on a stubborn stray, and felt a degree of satisfaction as it ran away and never returned.