Rot - and Yuk!

P - U! I need some advice ladies and gents. Do we have any gents?

Yesterday I noticed rot on Mountain Melody. I was able to pull out an entire green leaf from the rhizome. Rot and the end, and the smell. Ugh. Is the new leaf part of a new rhizome? I hope not.

I don't understand your question, but if you were able to pull out an entire leaf with no resistance and rot on the bottom end, you've also got rot in the rhizome it was attached to. Use a knife or sharpened spoon to scoop out all the rotted flesh, then dust the wound liberally with Comet kitchen cleanser (or another bleach-based kitchen cleanser) and leave the wound open to the air (do NOT cover with soil). That might save it.

Laurie

Thank-you, Laurie.

disclaimer: I typed the above before coffee and obviously now that I re-read it I was not awake. This is cracking me up and I hope all of the people who have read it are still not shaking their heads and wondering about me! LOL!!!!!!!

OK - here is what I was thinking that I obviously could not verbalize earlier. :-D I know that the rhizome increases after bloom and one should wait until mid summer to divide them. This is the year for Mountain Melody here. I was hoping that the rot was not on the new growth, but obviously I wouldn't know that until I dig the poor thing up.

Laurie did you have a fairly good success rate doing this?

Ah, one more opportunity to share my tough-love philosophy of iris gardening. I don't treat ailing irises ... period. If they aren't tough enough to handle what my growing conditions and climate throw at them, they are welcome to die and give me space to try a different iris cultivar. I'm a lazy gardener, and I have no interest in nursing weak plants. I reserve my nursing care for my 4-legged family.

That said, there was a time in my early iris years when I DID treat rot in irises ... thus my statement that the rot treatment recommended above might save your iris. In my experience trying a number of different methods to salvage rotting irises, I came to the conclusion that not treating them resulted in as many irises recovering successfully as did treating them, no matter which treatment technique I tried. So I just quit treating them and let nature run its course.

One single rotting rz in a clump might spread to other rzs in the clump and ultimately kill the whole thing, or it may not. If the clump is decently sized, you may lose a few of the rzs while the others grow on with no sign of disease at all. In my garden, the cvs that survive rot are usually the ones that are such vigorous growers that they simply outgrow the rot infection. Other times, a single rz or small clump may fall victim to rot and seem to disappear completely, only to miraculously resurrect with tiny new increases later in the season. For that reason, I don't dig out rot victims until I absolutely have to.

If you want to be sure you can save MOUNTAIN MELODY, don't wait till mid-summer to dig and divide it. Do it now. Discard the rotting rz(s) and any that look questionable adjacent to it/them. Take all the rest of the divisions from the clump and soak them for 20 mins in a solution of 1 part bleach/9 parts water. Rinse in clear water and then lay the rzs in a dry, protected area for several days before replanting.

Happy digging!

Laurie

This message was edited Jun 10, 2005 1:20 PM

Just stopping by to say yes we have a few gents - Mitch

That is interesting Laurie. LOL and I like your style. Anything growing in zone 3 had better be tough! I will do this afternoon, as it is in the path on the way to the greenhouse and I can't get over the unique odor it has. :-p

Hi Mitch! :)

Sue~

I agree with everything that Laurie has said, but, I just wanted to add a bit of extra advice.

I think what you are describing is bacterial soft rot. The most distinctive thing about it (as you know!) is the smell. But, just in case, I've included a description of Crown Rot (it can also be a bit smelly), because they have to be treated in different ways. As Laurie said, the affected rhizome(s) need to be scooped out THOROUGHLY and disinfected. I agree you need to dig up the plant as soon as possible and soak it in a 10 to 1 bleach solution. Don't wait until summer. Make sure to rinse off the bleach solution when you're done soaking it.

I also plant the rhizome(s) in another part of the garden. Bacterial soft rot is harbored in the ground, so it can creep back into the iris after you've taken care of the first time, especially since it now has a wound from being scraped. Also, as Laurie pointed out, make sure you allow the wound to dry before re-planting it. This will toughen it up and lessen the chance of anything else affecting it. I find that if the rot is really bad, I'll lose the mother rhizome but usually save the increase. If you've lost the increase, the mother rhizome may sprout out new increase if re-planted.

CROWN ROT is different, and caused by a fungus. You can tell if you have crown rot if you have white cottony growth on the surface of the rhizome and leaf bases. Small, tan spheres resembling mustard seeds are sometimes present as well. This must be treated by a fungicide containing PCNB, or Terrachlor. The rhizome must be soaked AND the soil must also be drenched with the fungicide as well. Make sure you don't plant anything in the affected spot for a while.

Another word of warning: DON'T use your digging and cutting tools again without disinfecting them. The bacteria or fungus can also be spread by using the same tools on other irises that haven't been disinfected.

I got quite a bit of rot on two clumps this year as well, and I usually don't get much, if any. As you know, we've gotten a large amount of rain here this year, followed by some warm and very humid days. A recipe for rot! I've talked to some breeders in the area, and they were having the same problem. It's usually worse in the areas where the irises are closest together, so make sure to give them good circulation.

I hope I've helped!

Laura



This message was edited Jun 10, 2005 12:26 PM

This message was edited Jun 10, 2005 12:27 PM

Oh you absolutely helped Laura! I will look and see if I can tell what kind of rot this is. Thank-you very much!

Sue~

Also, just a side note, sometimes my irises get a bit rotten because I don't cut the stems down all of the way after flowering. The rain then enters the stem and rots the rest of it, along with the top of the rhizome. It usually has a bit of a "stinky feet" smell, but not a "rancid meat" smell like bacterial soft rot. (How's that for a smell description? :-]) This is probably not your problem, but I thought I'd mention it.

It was not crown rot. This Iris had gotten so big the main rhizome was about 6" long and 3" wide! The increases had increases and it was growing in a semi circle. Two of the mother rhizomes were about 1/3 rotted. I was able to divide off several large rhizomes. The mother rhizomes, I just tossed. They looked done to me. A few of the increases had some small rot areas and I did the bleach/water dunk and they are now drying.

I really appreciate the help, Thanks again Laurie and Laura.