These were planted last fall. Did not bloom this year but they have grown.

Sorry, I have no clue. It looks like yellow paint!

Not paint but it does look like it

Looks a lot like leaf spot with out the brown center

Leaf spot is a fungus often caused by,too wet or poor circulation.

Fungi often cause yellow spots or blotches, but the bright yellow color could be from a virus. Some viral diseases cause a rather bright yellow color in the leaf. I don't know what kind of virus this might be in your iris, but here are some examples of virus pictures in other plants:

Cherry (scroll down to pictures 3 and 4)
https://www.canr.msu.edu/news/...

Rose mosaic:
https://ucanr.edu/blogs/blogco...

Has the symptom changed in the last few days?

Hmmm. These are dwarf irises and they haven't ready done well at all. I have been watering like crazy, perhaps too much. That would make sense. Other than reducing moisture is there a treatment?

Pull back the needles, leaves and other debris away from the rhizomes---these may be keeping the soil too moist.
It looks like the iris is planted next to a pine tree---maybe it is getting too much shade. Full sun is better. Although I see you are in Texas--maybe a bit of shade in the late afternoon would be OK. Perhaps someone from Texas can provide some input.

Well, that's a new one for me. My gut feeling is if it were a virus, that it might not just be on the outer leaves.. I'm pretty sure virus looks streakier, and runs along the veining, and isn't blotchy. Try cutting off the affected parts to see if that stops the problem. Most of the fungal stuff I've had with Iris usually disappears as the summer season progresses.. You might check the rhizomes to make sure they're not soft or mushy..

Definitely need to clear all the pine needles and leaves away from the rhizome. Not sure what the yellowing is but it could be a combination of too much water and too acidic soil (pine needles add to the acidity). Bearded iris do much much better in neutral to slightly alkaline soil.

If it were me, I'd dig them, wash them clean, powder them w some ajax power. Let them sit for a few days (in the house/garage, and then replant them in a new spot.

Frilly, do u mean Ajax as in scouring powder? I live in E TX and this is the land of roses, hydrangeas, azaleas, camellias. Still, my soil is nearly neutral. my regular irises planted elsewhere do great. This was my first time trying the dwarf varieties and it hasn't been smooth riding.

Thanks everybody for your input. It is very helpful,

Ajax cleanser contains bleach, which combats rot, but this doesn't look like rot.

Also, our soil is acidic, and my irises do very well in it, and I have never seen anything like this with our acid soil. To me, it looks more like a virus. I'd be digging it out, bagging it up and sending it out in the yard waste trash. I'd be concerned insects could spread it to my other itises.

This is a thread on mosiac virus on Irises.. The pictures look different than what's going on with your iris. Viruses are streaky and not yellow on Irises..
The thread "Mosaic Virus in Irises" in Irises forum

Have you tried cutting off the affected parts of the leaves to see it it spreads? I can't enlarge the pictures w/out it getting blurry to really examine the spots, but it looks like the patterns of something chewing on the leaves to me, but that color..... Has the color changed at all since you originally posted?

vossner said: Frilly, do u mean Ajax as in scouring powder? I live in E TX and this is the land of roses, hydrangeas, azaleas, camellias. Still, my soil is nearly neutral. my regular irises planted elsewhere do great. This was my first time trying the dwarf varieties and it hasn't been smooth riding.

yes like scouting powder, just a very light dusting. It can kill all sorts of things that might be going on and may prevent secondary rot since your plant is stressed.

It's hard to treat something if you don't know what it is. If the plant is stressed from whatever this is, digging it and messing around with ajax is only going to add more stress to the plant, any bleach based treatment is useful only if you're combating a bacterial rot issue.. This doesn't look like any bacterial kind of thing to me. If this is a rare and hard to find cultivar, it's worth trying a few of the suggested treatments like removing the needles which will add acid to the soil as they decompose. In the bed where my soil was too acid, many of the irses just didn't thrive, and just died out, I never saw anything like this from that condition. I did have a few varieties that did well in the acid soil though most did not. I called it the bed of death. Now that I've added a bit of garden lime to the soil and got the PH up, it's doing well. If the plant is one that you can replace easily, you might consider tossing it and getting a new one. I wouldn't plant another iris in that spot for a long time. Is there a lab somewhere nearby that you could send a sample to and have it analyzed? Could this be a result of the very high temperatures in your area? If you remove the affected leaves do the new ones still have this condition? There's just so many things it could be, yet not like anything I have seen before. Good luck with solving your mystery.

Have you sprayed anything, pesticide or anything else, in that area? Household cleaning products, car washing solutions, waxes, light oil, anything other than water? It looks like typical 'dribble' damage from something on the leaves. That it isn't spreading would indicate that it is transient and not continuing.

@CPPgardener That was my thought!

It looks like someone was spraying roundup and a bit got on your iris.

I think something less systemic than Roundup, which would affect the whole plant including any new growth. Something 'oily' most likely. It can be real surprising to see what some normally 'safe' things can do to plants.

Sprayed nothing other than water. I keep an eye I. It and spots gave not changed in size.