A really good plant is Coleus Canina also known as the pee-off plant. It has green foliage and spikey blue flowers in the summer. There is also a herb called Rue which is recommended
there is a plant called scareddycat. Not sure if thats spelt right.
Check out some gardening sites.
I think you can also get some kind of sprinkler that works on motion sensors. That way the plants get watered as well as the cat.
There are those prickle things for the top of fences but personally hate them cos they can do damage to them.
I have 3 cats so urge you please dont use anything that can harm them.