Iris rot

Pic of a clump of SDB with the rhizomes matted together much like a Japanese iris. Pulled on a couple of leaves and the entire top of a new rz came off. Dug and discarded.

Closeup. I think this clump grew from one rz in two years. I have 3 others so it is not worth the time and effort to salvage it.

I just hate that it got rot. It looks as though there was a ton of the plants. If it was something pretty, I would have cleaned and cut the rot out and doctored them and tried to save some of them. I just hate to let any of them croak if I can do something to keep them alive. After all, I'm still trying to cover that rolling hill out back. LOL The more irises the better. I must confess that my newest iris bed is really looking good and the fans are multiplying nicely. The old beds don't look too good and the mother plants don't have alot of babies coming up on them. Hopefully they will start to multiply a little better since it's cold off here some and I've been able to water the a little more. I just couldn't drag the waterhose and water them this summer when it was so darn hot for so long. Day Dreaming about beautiful Iris and DAylily blooms for next year. (grin)

I had dug another, different type of iris, adjacent to this one. I have a tendency to throw the baby out with the bath water when it comes to disease. I have a unproven theory that, once an iris is infected, it has a tendency to repeat the problem. Any time I find rot such as this or severe leaf spotting, I dig and discard the entire clump, sprinkle a generous dose of Comet, and leave the hole idle for a year. In this case, there were two completely unrelated irises with the same problem and I did not want to incubate the rot organisms so they had to go. Bleaching can only disinfect the surface of the rhizome so any bacteria present internally is free to reinfect the next season. Expensive or one of a kind irises may justify trying to salvage but most of them can be replaced for under $10. We have a yard waste pickup program here so it is easy to dispose of the discards. Placing them in your own compost is courting disaster with your complete beds.

You know I hadn't really thought it through like that. Of course your right, just getting rid of part of the problem and leaving it to spread to other parts of your garden could end in disaster. I certainly wouldn't want to compost the rotted irises and risk losing alot more plants. Thanks for opening my eyes just a little wider to see the harm in trying to save part of the plants that were infected with the rot.

You are right! I was still trying to save what I could by cutting off the rhizome and sprinkling Comet, etc. But will trust your last post I have a couple more weeks in MN and will see about any others that develop it & Will toss it. It's a soft/stinky/rhizome/rot...SSRR...Once you smell the leaf base you know for sure. I can't try to 'make it better'. Darn...

Throughout this, I've just discovered another rebloomer, 2 stems of Sugar Blues. DH said, 'They'd better hurry up...we're leaving in 2 weeks.' So life goes... ( if it hasn't bloomed, could I put it in a pot to take home?) Teasing...

One alternative to discarding an important iris would be follow the normal procedure of scraping and disinfecting the rhizome and planting it in a pot and let it grow for at least a year, keeping it isolated from others. It should either survive or croak and you do not take the chance of infecting other healthy irises. Just a piece of rhizome no larger than the tip section of your thumb can produce new growth with a little tlc.

This is a pic of a very small rz I wanted to keep to see what cultivar it was. It should survive the winter and produce good leaves next spring and possibly bloom.

Thank you again! I purchased 'Fancy a Flutter' this summer and found out why she wasn't 'flutterin' I'll pot her and also Parisian Dawn. Last year I had no soft rot at all, as far as I knew. This year I've had '6 soft rot', but no Iris borer. Hmmm..it is a puzzlement. I doubt if I'll ever have the percentage of awesome blooms as this year! I can only pray!
S#3

Oooooo Fancy a Flutter is a Blyth Iris. I just love all the Blyth irises. I really want Astro Bubbles are whatever it's called. Of course I have Champagne taste with a water budget.I'm not talking bottled water either I'm talking about tap water. LOL I keep getting out my Tempo Two Cat. and drooling over all my wants. All those huge lacy/ruffled irises with a slightly different shade 1/4 inch border falls are to die for. Think I'll go drag it out again and dream myself to sleep thinking about them.

Happy Gardening and day dreaming about beautiful blooms come Spring time.
Marian

I have had a lot of iris rot, unfortunately. I think that the bacteria is always present in ordinary soil, as are millions of other micro-organisms and it is more important to remove the cause of the rot rather than completely sterilize all the soil. I may be wrong. Borers, slugs, wetness, crowding - this is what I would target. Last year after dividing and replanted many remnants that had had some rot in the plants I had some left when I ran out of steam and I planted these in potting soil and overwintered them in the garage. Some died. but most of them are growing well. I am going to keep them in pots so I can control how much water they get.

A pic of the above nubbin today. Small rz's can be salvaged if they are from a critical plant.

I have spot treated rot on many occasions by trimming and treating the plant in place. I even use Clorox Cleanup directly on the plant and trim in the garden. Sometimes the plant must be dug and thoroughly trimmed of rot, sanitized and replanted. I have saved many plants that have gone on and produced stalks the next year. I am glad I did not dig and destroy. Clorox Cleanup is useful when dividing to treat the points where the iris were separated. Comet is useful as well. I use either or both given what the conditions are.

The organisms are present in the earth at all times. It is the conditions in a given situation that allow them to flourish into a problem. I find it to be a temporary isolated anomaly, not a spreading disease process.

This works for me. I start with a minimal approach and monitor. I have NOT found that if a plant has rot that the plant next to it is more likely to develop it. I spray Clorox Cleanup around the affected and treated plant as well. I may need to spray it several days in a row as monitoring indicates.

K

This message was edited May 1, 2011 7:35 PM

irisawe......Your thoughts in the previous post about soft rot echo mine. You put it well. I have recently been discussing soft rot with a friend and will recommend that she read your post.

I finished spraying my irises for the second time this spring. We have had a very wet spring and if weather has anything to do with fungi and rots, this should be the year. I found some Hi-Yield fungus treatment with chlorothalonil as the active ingredient. Anything would be better than my last few years.

I'm relatively new at growing irises and really learned alot about how to handle rots and borers by reading this thread. I think I may have a problem with a few of my irises. I found a broken off flower stem that was all mushy and rotten at the base while I was weeding yesterday. If I don't find any actual borers, how will I know whether it's rot or borer? Oldgardenrose. . . . I read some of your other posts about how to treat for borer. Very helpful. What's the name of the Hi-Yield fungus treatment you found?

I see more rot on my few new iris.
I also found a slug. Its just too wet here.

The Hi-Yield fungicide is 'vegetable, flower and ornamental fungicide'. Active ingredient is cholorothalonil 12.5% which is the same as Daconil except Daconil available thru big box garden centers has a much less concentration. I use it in a common plastic tank sprayer adjusted for a heavy mist. I add a couple of ounces of liquid soap concentrate and a couple ounces of Sevin. I just sprayed mine the third time and, so far, no leaf spotting after one of the wettest springs we have ever had.

According to most of the info available, once the spotting begins, treating with fungicide will not work. It may be helpful to saturate the soil around the rhizome to help kill the organisms in the soil as others above have explained.

Salvaging rotted rhizomes is just a matter of personal preferences. I only have 2 or 3 which would be difficult to replace so I just discard the ones with rot on or in the rz. Changing beds is a good solution if you have spare areas available. Crop rotation is done for many good reasons and should be practiced when possible.

What a great resource you are Oldgarden rose.
When I saw the slug I drenched with Imidiploide just because it was supposed to affect soft skinned critters.
I havnt checked the plant lately but will in a few more days.
I garden in clay and amend with some gravel( stone-sand) I also dont have a dozen iris alltogether. I cxant imagine what rot would do to those huge beds I see in photos here.

You should use Sluggo for slugs. It is supposed to be non toxic for people animals and soils. I just noticed some rot today and sure enough there were some baby slugs there too. I put out sluggo early this year but it must be time for another dose.

I have used sluggo on all gardens.Its over rated but thanks for the referral.
I have many hostas and the light green -yellow ones are the slug favorites. I use a drench in early spring to kill as many as possible. 1 part amonia to 10 parts water. pour sround the hosta eyes as they emerge in spring. I really think this has cut down on them here where it seems to be damp all the time.
Lived here 4 years. Started the drench last year and noticed fewer. Up until then they ate everything.Ligularias are special treat for them.