Climbing cutworms are currently quite active.

To verify, look for them around 10 pm, with a flashlight. The commonly align with the edge of the leaf or along the flower stem.

When found, pick it off, then drop into slightly soapy water or stomp on it.

Iris borer were prevalent where I used to live, in the MWest. They don't do what you've got. The larva tunnel down a leaf leaving thin transparent stripes down the leaf, I think later in the summer. They then live in the roots and eat the iris from below. You do end up with mush but the damage is below ground as they do they're work as grub type things. I have not seen any sign of them here in the NW. I would go with Jean's suggestion of cutworm. So many irises look so ratty this spring with black tips on leaves - guess the cool and excess rains after that dry warm time (when was that? months ago?) must be causing problems.

I was just assuming slugs... I have some of the same damage. I don't have it on all my iris, just a couple of plants. Is it cutworms? I'd be curious to know.

It seems in my garden, both slugs and cutworms cause similar damage to my iris. When I have gone out at night, I find them both at work.

I have had alot of slug and cutworm damage to my iris and clematis this spring. Neem oil works great to get rid of cutworms. My plants were being devoured every night and now they are growing great after the neem oil.

That's good news about neem oil. I had treated most of my gardens with nematodes to control root weevils last fall and those parts are free of both weevils and cutworms. Luckily the nematodes are also a good control for cutworms. But the parts I skipped are full of hungry cutworms. I'll give neem oil a try.

Sounds like we are all having similar issues with Iris this year. I have basically the same problem. It's been so wet here, I wasn't sure if it was some kind of worm, iris-borer, all the moisture or a combination of all. I have neem oil, and am going to try that, too.

Some iris are worse off than others. Upon further inspection based upon the advice given here (THANK YOU ALL!!), I did find slugs. I never knew how much damage these suckers can do to an iris. Now I know. I've been looking for them several times a week. I know it is probably not enough but I will keep at it. I am also noticing several iris with some rot. Which I have read is common and indicates that large clumps need dividing. It looks that way to me! They really do 'spread'. My next purchase for control will be 'Sluggo' which I have read is safe for dogs.

What about iris boors, how do you control those?

Ynuk ynuk ynuk.

Bearded iris tend to get all spotty and funky after bloom here anyway, so bugs or not you end up cutting them back. Pure Iris pallida forms may be less susceptible, I often see these with good foliage appearance for much of the season.