[RStar]

Some of the damage you describe is not typical of snails. They usually don't climb real high into the trees, or even bushes like hybiscus. It sounds like (and usually is) more than one pest. The hard to reach leaf chewing is often done by grasshoppers or locusts, and other than hitting them over the head with a hammer, there is not much you can do that won't also poison you. Catapillars are another suspect, and there are some good products you can use on fruits and veggies that are safe. Spending time in the garden and watching the wildlife is the best way to see what is going on.

To figure out the snails/slugs, go out with a flashlight as late at night or early in the morning when its dark, that's when they are out. You can then see what they are up to, and you can simply pick them up at that time. The plated of beer or traps made to be used with beer are one way, but I have had good luck with deadline. What ever you choose, be diligent. I have, and I haven't had a snail in years.

Good luck!