Question about splitting iris

[jerryshenk]

We have two large clumps of iris that probably haven't been split in 20 years...or 30. They are flowering but I think they would flower more if they were split. I'm thinking of digging them all up in August, removing the older rhizomes and any that look bad (not sure what that means;) and then putting them right back where they were. My main question is, will they bloom next year? If not, maybe I'll do one section this year and one next year. That's my main question for now - I haven't don't too much research on specifically what I need to do.

Here's a picture of the iris clumps that I'm talking about:

DSC_20130518_075602 by jerryshenk, on Flickr


And one bloom - hard to shoot in a group 'cuz being all white, they wash out.

DSC_20130518_082448 by jerryshenk, on Flickr

[kHT]

Sounds like a good plan!! According to what I have learned you can remove the center of the clump and leave the outer ones or you can do the entire clump.
It is my under standing that the new rhizomes are what you want to replant. Also it is best to do this every 3-4 years, with the best time to do this is July, August
or September in good drained soil. If you are hot during this time it's important to water so they don't dry out. I have move them as late as Dec. with a mild
winter and yes they still bloomed. Spacing according to my book is 12 to 24 inches apart and I find this way it give them time to grow!! Water them deeply but
don't over water them. Just keep the iris bed clean, weed free and allow the tops of the rhizomes to bask in the sun. Important is that the bloom stems should be
cut off close to the ground after they bloom. They say to leave the green leaves undisturbed but we here cut them back to 3" and haven't had a problems when we
tidy up the gardens after the spring bloomers are done. Of which they can regrow and in the fall we do it again. Always removed the diseased or brown leaves. Hope this
helps.

[party_music50]

They will bloom next year provided the rhizome pieces you replant are large/mature enough. Once you dig in and lift a clump you should be able to tell what rhizomes to keep and which to toss. Toss the pieces that are decayed, gnarled/elongated, without any new growth, etc. Also be sure to inspect for signs of iris borer larvae and handle accordingly (i.e., destroy borer and, if it can be saved, cut away any rotted parts of rhizome). The mature rhizome will usually be "Y" shaped with the new growth coming from the top parts of the Y -- and that's the direction the plant will continue to grow, so replant accordingly.

When I re-do my iris beds I lift a section, shake off the dirt while separating and selecting the rhizomes I'll keep, I then cut their leaves back to about 6-8" high, put a clean cut across the back end of the rhizome (bottom of the Y), trim back long roots (all new roots will form once it's replanted), and then I let the rhizome dry for at least several days, if not weeks, on newspapers where it is protected from the elements and has good air circulation.

Be certain not to cover the entire rhizome when you replant -- it needs to be at least slightly exposed or the iris won't flower.

PS: for some reason your photos didn't show for me prior to posting. Those clumps don't look like they've been unattended for that long!

[jerryshenk]

Thanks for all the advice. It seems like killing iris is pretty difficult so I should be ok;)

I think I'll let the leaves along except for removing dead ones. There are other plants around to "take the spotlight".

I moved a clump last year and I guess I planted it too deep - it didn't bloom at all but did last year. I put it just barely under the soil...definitely not "totally exposed". I'll have to go out and sweep some dirt off in hopes of getting blooms next year.

I don't REALLY know how long things have been unattended...some poison ivy vines were quite a bit larger then the base of my thumb and they reached 25' into some trees, daffodil clumps with 80 bulbs and 3 blooms....let's just say that the plants here are very mature;) The iris only had a few blooms the first year, this is by far the best year for them but I think they could be a lot better.