What's Eating My Roses?

I don't know a whole lot about garden pests, but something has been chomping on much of the garden. So far it's been the rosebush, all three redbud trees, the purple plum tree, the lamb's ear, and the bloody sorrel plant. The only thing I've seen are some hideous looking things on the rosebush. The big ones are green and grasshopper-like with striped antennae but still only less than a centimeter. The littler ones look the same but are dark orange. I haven't been able to get a picture of them yet and can't verify that they are the culprits; but I'm squishing them anyway!