drebenc, I have a thread here with almost the same title, because I've been having a similar problem.

My culprits were small, shiny black beetles that neither my local nursery nor county extension service recognized. Sometimes they'd be on the leaf proper, and sometimes they'd be wedged in at the leaf base where it joins the stem.

I started treating the plants with a bacterial spray called Spinosad. It seems to be helping after a month, as I've seen less damage, and thankfully the little demons haven't spread all over the yard. (Some small spiders also started hanging around the area, and they may have helped out, too.)

Some of your leaves look like they've been "shot," which one page I used said is a possible sign of flea beetles. (That's not what I had, though. My residents were too large.) The county extension service also told me to carefully check under the leaves at dusk for caterpillars, but I never did find any. (They prefer my poor, embattled nasturtiums at dinner time. :p)

Good luck.

Thanks for your reply as it has been very helpful. I will research what you suggested it could be and the other thread. Thanks again!