Hi Whitney,

I'm sorry to hear about your columbines!

A few culprits are possible, but one of the most likely is the columbine sawfly.  These ant- and bee-relatives resemble small green caterpillars and can consume the leaves of a plant in short order since there are usually quite a few of them.  The will pupate on the ground near the plants; there's only one generation per year.  Your columbine should be able to push out a new flush of leaves within a couple of weeks and recover nicely; multiple years of defoliation, though, can significantly weaken your plant.  Scout early in the year when the columbines are beginning to grow to look for the sawfly larvae and manage them early if you decide it's warranted (a big outbreak this year, though, doesn't guarantee one next year).

This fact sheet from our Extension colleagues in Wisconsin has some more information about sawflies as well as other columbine pests: https://hort.extension.wisc.edu/articles/common-columbine-pests-columbine-leafminer-and-columbine-sawfly/

I hope this is helpful!

Cordially,

John