I don't know about the holes- they look like snail or slug damage to me but I understand that there are other pests in your area, including the iris borer. You can examine for the borer by looking way down in the leaves near the rhizome. Some people just squish them. The borer lays its eggs in mulch, like what you have around your irises. You should clean up all of the leaves and debris from around your irises to about three feet and dispose of it to be sure you have eliminated iris borer eggs.

The first shot looks like rot to me. Irises cannot stand to be mulched, and the tops of the rhizomes must be exposed to the sun. Push on the top of the rhizome to see if it feels spongy. Be sure to clean out all leaf litter from between the leaves of your irises. That's really the main trick to growing irises.

Good luck!
Renee

I have other plants around the irises to within a ft or so, so I did the best I could to move away the mulch. I have some sluggo I can put around them for slugs or snails. I'll go do that. :)
I hope it's not that iris mosaic virus! Ugh!

Hi Kenstar,

The holes definitely look like slug or snail damage. The yellow splotches on the leaves looks like signs of mosaic virus.

Contrary to what Renee stated, I have always mulched my irises, and found that they grow better and have bigger rhizomes than those that do not have mulch. Don't bury them under the mulch, but light a application should suffice. I've had a lot success with mulch, especially with my perrenial garden, where I'm watering every other day. It is essential, that you have good drainage...otherwise, mulching is not suggested.

I also noticed that you are growing Heuchera next to the Iris. Heuchera is a shade plant, which leads me to believe that your Iris are planted in shade...if so, you must remove them so they receive more sunlight.

Carlos
Brighton Park Iris

I really don't have anywhere else to put them. I'm out of room lol!
They did bloom last year and did great. I also had them mulched last year.
I figured that they get a lot of the sun they need before the tree's leaf out. I might be wrong...
In the summer, they do get a lot of afternoon sun, as the bed is facing west. My heuchera's do just fine with that too. I have them all in a raised bed, so drainage isn't an issue and I am very good at keeping everything watered.
If it is the virus, which I think you are right about that, do I have to dig up that particular clump? Will it spread to the others?

I have dug up the one fan, but don't know if it will spread to any others in the vicinity. What a shame! They bloomed and looked so lovely last year. I guess I'll have to be more vigilant about aphids this year. I don't like or want to spray at all, so I don't know what else I can do. Any suggestions about what to do about aphids?

I have the same hole damage on just a few of my TB's and couldn't figure out what was causing it. Some of the holes looked almost perfectly round.
Is sluggo the best for this type of treatment?

Julia