I can't be sure, but it might be a beneficial predator such as a syrphid larva. Do observe it and see what it's up to. Worms that eat leaves can be seen eating leaves, while predators usually prowl around. If you conclude that it is eating leaves, just pick it off and squish. Or are there hundreds of them? True caterpillars can be controlled with a biological insecticide, BT (bacillus thuringensis). The worms that most commonly graze on rose leaves are rose slugs, Look for them on the underside of the leaf. This post was edited by michaelg on Tue, Aug 12, 14 at 12:10

Have you seen any worms on yours, boncrow66? Since I've had this problem in previous years without seeing any, I figured it was something tiny or a night feeder and was surprised to actually see of few of them this weekend. I googled green worms on roses before I posted, but really couldn't tell...maybe tobacco budworms...I grow a lot of nicotiana. I always have bug holes in the leaves of my flowers...nicotiana, cleome, angel's trumpet, coneflower, milkweed, etc, but holes in leaves really don't bother me...would prefer bugs/worms don't eat my rose buds, though.

Probably something like cabbage loppers but I'm not sure. I haven't seen many this year, I think they usually get me worst when the rains come though. Anyway, to control leaf eating caterpillars you want to use BT, bacillus thuringensis. Dipel Dust or Thuricide are products I know of out there for it. Last I tried, Lowes didn't have Thuricide but HD did. Ya mix it up according to the directions and spray the plants well (drawback is you don't want to be straying it during or right before the heat of the day which might leaves you spraying in the dark.) Dipel dust might be easier if you can find it but I haven't found it here in FL. Anyway, the caterpillars have to eat some of it for it to be effective. It is a bacteria specific to the guts of leaf eating caterpillars and it will give them a bad belly ach, they quit eating and eventually die. It requires re-application after rain if the caterpillar problem is still present. There are similar products that attack mosquitoes (mosquito dunks) and I believe there is the milky spore that can be used for the under ground grubs but I've never tried that.) I've used Thuricide and mosquito dunks and they are pretty safe as far as pesticides go. They do not hurt beneficial insects and they are safe enough for use in/around an aquaponics system with fish and bio-filter bacteria. Here is a link that might be useful: TCLynx

That is actually a Hairstreak butterfly caterpillar. They are beautiful butterflies, and if you can find a more expendable hibiscus, put it on that. Good Luck!