leaves chewed on perennials and annuals

Something is chewing on the leaves in my perenial bed, and on the few annuals I have in there. They start from the ground and work their way up the plants. Any idea what is doing this - and how to get rid of them? Thanks!

 

Could be almost anything from insects or slugs up to deer. A photo of the damage would help.

 

Thanks Micheal....it is definately insects.....and my camera is missing. Will post a picture when it is found.
The insects are gradually eating most of the leaves....leaving the stems. They gradually work their way up the plant. Dont know if this info helps, but the best I can do right now. Thanks for replying!