A few holes I can contribute to leaf cutter bees, but this poor plant is getting chewed on viciously - slugs? I haven't seen any tell-tale slime trails or the creatures themselves. I found a couple very small ones in another area, but not around this one.

Really hard to tell who's the culprit unless you catch him in the act, Greg.

Go out after dark with a flashlight, or very early in the morning after rain or watering has happened. Look on the under sides of the leaves with the flashlight. Look carefully under the bottom-most leaves too. If slugs or snails are hiding under there they wouldn't necessarily leave a trail.

Could be slugs, or snails or caterpillars or bugs.