Another question

While weeding my iris (TB), I discovered three that each had a section of fully, rotted, stinky rhysomes (under newly growing fans). Should I dig these up, trim off rot, treat with sulfur or something and replant? Or should I just try to cut it off in the soil and try to treat the cut area of the rhysome in the ground and not disturb the other roots.

Seems to me the rot might spread if left in the ground, yet I know that the old rhysomes deteriorate in the ground. It just bothers me that these are all under new growth so it's not old rhysomes.

Back when I used to treat irises for rot (which I no longer do - it's strictly survival of the fittest here now), I saw no particular difference in the effectiveness of treatment whether I treated in-ground or out. Even if I dug them, cut out all rotted flesh, did the bleach soak, and dried them for several days before replanting, some continued to rot after they got back in the ground. Some treated in-ground continued to rot, as well. Some in both groups recovered.

After I stopped treating for rot, it became evident that some irises spontaneously recover from rot infections even without treatment.

Frankly, I think treating irises for rot is a waste of time. You're better off correcting the cause (poorly drained soil, insufficient sunlight, overwatering, overcrowding, insect damage, inappropriate fertilization, etc.) than trying to treat the disease. If you can not identify a specific factor that leaves your irises vulnerable to rot infections, then perhaps the particular cultivars that are rotting are simply weaklings that are susceptible to rot. Even if you manage to get them through one bout of rot, those are the irises that are likely to keep rotting whenever they get stressed. Do you really want to waste valuable garden space on wimpy iris cultivars when there are so many strong, disease-resistant irises available?

Just a little food for thought.

Laurie

But, Laurie, sometimes it's the challenge of seeing if you can rescue a plant. I scrap out the rotted part and have had great luck with Comet cleanser.

All Together rotted for me each winter for three years. Each time I managed to keep a piece alive. Now I have a healthy clump of it.

Neil

I have used more Comet this year than I have in my whole life! And no, my house is not spotless! I use a spoon to get as much rot as possible out. Sometimes I use a knife and cut just around the new fan and leave enough of the roots for it to grow. Then sprinkle on the comet . I've had pretty good luck with mine this way. I have also just poured a 10 part water to one part bleach all over the entire clump after I pulled the rotted fans away! It worked also. Good luck.

Neil, you make a valid point. I, too, have had new-to-me irises that have been very susceptible to rot for the first few years until they have acclimated to my climate and growing conditions, then ultimately become healthy clumps. Far more often, however, those slow-acclimaters succumb to rot and die out of my garden completely. Gardening is challenging enough here in northern MN without putting extra effort into babying weak irises to see if, maybe, they'll decide to get healthy in a few years.

Laurie

This message was edited Oct 1, 2006 8:46 PM

I've had great success treating rot with 10 % bleach solution, drying out then and replanting. No more rot. But I'm one who can't easily stand by and do nothing. It's my nature, I have to try and help it out. It has worked.

I do thank all of you experienced iris growers for your thoughts. There is a lot of food for thought here and some very interesting information. I had no idea you could use Comet Cleanser.

Kay

You can use any bleach-based kitchen cleanser for in-ground treatment. Some folks have reported success sprinkling the wound (after the rotted flesh has been removed) with sulphur, lime, gypsum, Comet (bleach-based cleanser), a bleach/water solution, anti-bacterial dish soap, fungicides, and I'm sure other stuff. Or maybe some irises are just recovering in spite of it all. ;-)

Laurie

My method is to dig up the infected rhizome. Scrub away all the mushy part in bleach water. Then let the rhizome stay dry a few days in my sunny kitchen. This works if there's a good piece of the rhizome left, but if hardly anything is left to salvage, then usually the rest of the rhizome quickly disappears.

Some things I just feel compelled to try to save, especially the new stuff that I haven't had a chance to see bloom yet.