Might be something moving around in that bark mulch. I never have luck growing immature hostas by surrounding them with mulch--they tend to get eaten like that as well (just my experience). My advice is to clear the mulch from the base of the plant and maybe put down a ring of insecticide around the plant.

Little holes are usually slugs. Big holes are usually some kind of caterpillar. (you could have both) Go out after dark with a flashlight and you might see what is eating it. The caterpillar will be gone about 2 weeks after they hatch. In that two weeks, they continue to eat more every night. If it's slugs, they will continue to eat until you kill them.

There are various treatments for each of them. For slugs - drown them in beer, shoot them with 10% ammonia, apply Sluggo, etc. Sluggo Plus is supposed to help with caterpillars. I use Dipel Dust for caterpillars. I usually sprinkle it on the ground, not the leaves, as it doesn't wash off well, especially on blues.

I agree with Tony. Pull the mulch back to the drip line.

Someone else might have some ideas as well, as I don't have much of a slug problem.

bk

I do have a slug problem so I save eggshells through the winter... actually, all year... and when my hostas begin to emerge in spring, I spread crushed eggshells heavily around the base of each plant. Slugs won't cross the eggshells because the sharp edges cut them. When the shells finally disintegrate, they add nutrients to the soil.

The slugs, deprived of their preferred diet, move on to munch holes in other perennials so I'm widening my application to include other plants in addition to hosta.

I crush the eggshells with a potato masher.

This post was edited by gardenweed_z6a on Wed, Jun 18, 14 at 19:32