Since lime will lower the PH of the soil, it might be best to test the soil first. I think bearded irises like a neutral PH, although I'm not sure.

Good advice Tom.....

Since my soil runs acidic (hence the moss) I don't think PH will be an issue, but that is a really good suggestion Tom.

Thanks for the suggestions everyone!

I have the opposite thing here. There is a lot of lime in my water supply. I think I'm living on an old lake bed. We have a lot of limestone in the area, along with aquatic fossils.

Tom - your area was part of a glacial lake that whittled down to become Lake Michigan. The limestone is part of the karst topography of your region. The geology of Wisconsin is pretty complex due to areas that were heavily glactiated and other areas that retained pre-glacial features (the Dells area).

So, you have natural lime in your soil, do you have much rot? Of course the amount in the soil might not be enough to be effective.

Which made me wonder about the early spring application that Blyth suggests. He says to use a light sprinkling that will melt away by bloom time. If it is a very light application then it shouldn't change the PH of your soil for any long period of time, especially with spring and summer rain. It will leech out.

I'm not sure Australia has summer rain. They might be more like us. Almost all of our rain comes in winter and very early spring...November - March.

Lime raises the pH in the soil, making it more alkaline. Seven is neutral. Anything below is acidic, anything above is alkaline. Now if you want to make a heavy clay soil drain better or leach out salt in the soil and replace with calcium, use gypsum. Gypsum doesn't effect the pH one way or the other.

It depends where you are in Australia. They have a rainy season in late fall/early winter (Feb-April) and then again in the spring (Oct/Nov), unless you are inland, which is desert.

True Ken, but I want to use it (lime) to reduce chance of rot.

Ahh, so giving them some lime (as the bloom stalks are coming up) is like giving them a booster shot of calcium which helps ward off the rot,(is what I am guessing) or it might just kill off the bacterial rot.

Not sure of all the dynamics, but I am willing to give it a shot. We have had lots of rain this year so, as they say, an ounce of prevention....!

I have my share of rot, last year more then most.

I battle moss in all areas that are not grass. I began liming my Iris beds a couple years ago -- I'm tickled pink that it's recommended for Irises to deter rot. I can kill a lot of birds with one stone, since our soil is very acidic. Thanks for the information!!

I'm having trouble with with liverwort which is closely related to moss. I wonder of lime would help with it? Hmmmm.....

I would think it would kill it, Marilyn. Lime is used to kill moss...........................

It might be worth getting a small amount to experiment with.

Yes indeed!!

NOTE about Lime: DO NOT spread it around Japanese iris. It can kill them. They have opposites needs in that regard (much like they love manure that would rot out TB's).

Thanks for the warning Leslie!