Try something prickly like Pyracantha. You can also use the twigs to protect other plants as they are very thorny.

Rue (Ruta graveolens) will repel cats, but it likes at least some sun.

I have the same problem, every morning I find another little pile or plants raked out. If there is the slightlest space.... I have pots and twigs and mesh netting all over the place. Hopefully when the plants grow a bit it may improve, but with 5 cats (not mine) in the area its a continual problem. I have just bought some cat repellant from the garden centre but dont think it much good putting it down while its still so wet.