I love the rich, velvety look of dark purple and dark blue irises, but mine tend to get a few little white speckles on the falls. What causes that? Can it be prevented?

Usually, I suspect drops of dew...or rain.

I've been having a lot of problems with white marks on the dark velvety falls this year, too. It is really irritating. I'm not sure it is rain, because we haven't gotten that much rain, but I guess it might be dew. It's not just speckles, either, but streaks as well, and it is not all the dark irises, just some of them. I would sure like to figure out how to prevent it, but

Mine don't appear to be water marks; I was just wondering if it might be scarring from bits of sand that are blown against the falls. I will need to be more attentive and see if the irises that are not exposed to the wind (we are in a windy area) get the same little white specks where they're not supposed to be.

Sometimes I get white strings on them that I am pretty sure are spider webs that have gotten blown against them. I haven't figured out how to get them off, but at least they don't cause any damage.

Lynn, I think you may be onto something. My worst problems are on the dark iris that I have in my front yard, which is on a very busy street. I've wondered if the marks are from tiny bits of debris thrown up by the passing cars. I've thought about moving my
dark iris to the back.

Freezing, or near freezing, temperatures at late stages of bud development can create white marks on the falls. It can happen to the standards, too, but they are less vulnerable to damage being tucked more deeply into the bud.

Interesting info, Kent. I had not known that before. Thanks!

Thank you, Kent! Let's hope for some warm weather in March and April next year!