The grass did come back with a little help. You can't really see the color variations here on a sunny day, but you can
see the seams between the stamps where its a bit wider and not perfect. Stamp work doesn't totally look like the real thing.
It looks like concrete, but the cats don't mind. Using texture mats rather than stone patterns is much easier, by the way.
Liquid release agent is also much cleaner and less toxic then the powder, but you don't get the color variants.