Maybe some sort of night feeding caterpillar? Try scratching the soil around the base of the plant and see if you can find any. I had a terrible problem with these one year. It wasn't until I dug in the soil around the plants that I actually found the critters.

They started at the base of the plant and went almost all the way to the top.

Kevin

Rabbits? When my asiatics disappear from the bottom up, it is rabbits, the holes in the upper leaves my be completely unrelated. Maybe not, how far up did the other plant get munched?

Cathy:

That's so frustrating! I have not grown balloon flowers before but this year when I put down new mulch in one of my beds the earwigs moved right in and had a heydey. If you have mulch down and moist conditions they could be your culprits. Since those insects are on the move at night it took me a while to figure out what the problem was as I did not know to look under the mulch.

Hope this helps.

Kate

Foliage of my platycodons were eaten from bottom up by woodchucks and they bloomed on a leafless stalks this year.
Ugly sight :-((

Thanks, you guys. It's still a mystery to me, and outdoor bug spray hasn't helped. It apparently does occur at night. I've only got a couple plants and don't want to lose them. Maybe I'll move them across the yard to another bed and see whether whatever's munching can't find them there so they can survive.

Just an FYI about the bug spray. If it is earwigs that probably won't really affect them. I tried to spray my plants with that also to absolutely no affect. However there are some interesting suggestions here on GW for identifying if earwigs are the culprit and how to deal with the little darlings.

Kate

I read somewhere that woodchucks/groundhogs eat them.

Hmm. Thanks for the ideas. Could've possibly been earwigs, as they go after our peaches big-time. But we're in the city, and I've never seen woodchucks or groundhogs in our area.

Are you familiar with cutworms? They cut off thin stems a few inches or less above ground level, or cut off leaves from larger stems. Often they leave piece of the plants on the soil's surface, though not always. They spend their days curled in loose soil near the base of the plant within an inch or two of the soil's surface. If you disturb them they curl up into a tight spiral. Go out with a flashlight at dusk and look near the base of the plant and up the stems. The cutworms vary in color from tannish to greenish to brownish, and the youngest will be less than 1/4" in length while older ones can be up to about 1 1/2". You can squash them or drop them into a container of soapy water. After dark they migrate over the garden's surface to find new plants, so you may need to check more than once. With small plants you can give them a plastic collar that goes an inch or so below the soil surface and a couple inches above to discourage new cutworms from finding your plant.

It’s rabbits, definitely rabbits! I’m so mad right now because again this year they’ve devoured mine. Woke up and watched one having a feast on them outside my bedroom window! I planted marigolds by them hoping that would work. Nope. So disgusted!😡

Try Liquid Fence.

My thought are it could be slugs. They can be very damaging. They come out at night and hide in daytime so you don't see them unless you go out at night with a flashlight. There are many ways to combat them. Do a google search on slugs for suggestions.