Irises forum: Advice for Spring Clean-Up

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Name: Jane H.
Kentucky (Zone 6b)
Irises Birds Region: United States of America Region: Kentucky Clematis
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janielouy
Feb 15, 2018 5:48 PM CST
Well, the temperature are way up there (72 degrees today) in Kentucky so clean-up time is coming although we still have more winter to come. There has been so much rain that the leaves (fans?) are all limp and covered in leaf spot.
Should one cut them off with scissors because if you pull them off you might heave the plant? Do you have to disinfect your scissors between or is that necessary (time-consuming!!)???
Name: Leslie
Durham, NC (Zone 8a)
Region: North Carolina Irises Cat Lover Garden Photography Enjoys or suffers hot summers Celebrating Gardening: 2015
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Lestv
Feb 16, 2018 7:58 AM CST
I would cut off only the affected part of the leaf, leaving as much as possible to help gather energy for the iris. I have never disinfected after every cut. Maybe some have? It would seem more effective to trim them all, then spray them with fungicide to contain the leaf spot.
My road calls me, lures me west, east, south & north; most roads lead men homewards, my road leads me forth. - John Masefield
Name: Jane H.
Kentucky (Zone 6b)
Irises Birds Region: United States of America Region: Kentucky Clematis
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janielouy
Feb 16, 2018 9:55 AM CST
Thanks. I used to cut them back in the fall but thought I should leave the green but now they look so awful with all of this rain that I may go back to that. I will spray with a fungicide as suggested after they start to grow back.
(Zone 9b)
Region: California
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UndertheSun
Feb 16, 2018 11:31 AM CST
I disinfect my hands and scissors after every plant and remove only the infected portion of the leaves. If the leaf spot is all the way to the base of the leaf, I cut it as far down as I can go. As soon as your weather will heat up (and dry up) the sign of leaf spot will go away (on the new leaves).

Name: Jane H.
Kentucky (Zone 6b)
Irises Birds Region: United States of America Region: Kentucky Clematis
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janielouy
Feb 16, 2018 11:37 AM CST
What do you disinfect with? Bleach? Other product? Wow! Lots of work but it pays off down the road I guess. I was thinking maybe you posted something like this one time.
(Zone 9b)
Region: California
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UndertheSun
Feb 16, 2018 11:42 AM CST
I take a small bucket of diluted bleach water with me. I'll also continue to dip the scissors into a cup of Comet. Make sure you're wearing clothes and shoes that you don't mind getting some bleach damage.
Sweden
Bulbs Lilies Bee Lover Irises Hellebores Deer
Celebrating Gardening: 2015 Photo Contest Winner: 2016
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William
Feb 16, 2018 12:35 PM CST
I agree with the bleach treatment. It can also be worth having two pairs of scissors, so you can use one while the other is soaking in bleach.

The reason I like to sanitize my cutting tools is not specifically fungal leaf spot, but there are other more dangerous pathogens as well. For instance, I wouldn't want to transfer bacterial soft rot, nor bacterial leaf spot between irises. An open wound is very susceptible and at the time I cut I may not even know that a specific plant is infected.

As I grow lilies, I'm also very aware of the risk of transferring virus between plants. Irises seems quite tolerant when it comes to viruses, but it seems unnecessary to take the risk. Viruses can affect plants, reducing vigor and so on, even in ways we don't notice easily, so taking some precautions here seems wise to me.
[Last edited by William - Feb 16, 2018 12:36 PM (+)]
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Name: Leslie
Durham, NC (Zone 8a)
Region: North Carolina Irises Cat Lover Garden Photography Enjoys or suffers hot summers Celebrating Gardening: 2015
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Lestv
Feb 16, 2018 12:42 PM CST
You guys must get awfully serious leaf spot to go that crazy.
My road calls me, lures me west, east, south & north; most roads lead men homewards, my road leads me forth. - John Masefield
Name: Tom
Southern Wisconsin (Zone 5b)
Irises Vegetable Grower Butterflies Region: Wisconsin Keeps Horses Cat Lover
Dog Lover Keeper of Poultry Daylilies Celebrating Gardening: 2015
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tveguy3
Feb 16, 2018 12:49 PM CST
I guess I wonder if you have stopped the leaf spot doing this? I don't bother doing anything with leaf spot at all. It comes and goes, some years worse then others. My guess is that the bacteria is air borne, and will be around despite anything you do.
I am not afraid of an army of lions led by a sheep; I am afraid of an army of sheep led by a lion. - Alexander the Great
Sweden
Bulbs Lilies Bee Lover Irises Hellebores Deer
Celebrating Gardening: 2015 Photo Contest Winner: 2016
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William
Feb 16, 2018 2:20 PM CST
Leslie, yes I do get a lot of leaf spot. There are many rain days here and little sun, even more so as I live in the forest. However, as I already mentioned, for me personally, sanitizing my cutting tools are not primarily about limiting spread of fungal leaf spot. Smiling There are more important pathogens to worry about, which may or may not be problem for you at this time.

Tom, to answer your question there are both fungal and bacterial leaf spot, so their way of spreading are different. Bacterial leaf spot infects the leaf tissue(but not the rhizome) and spreads by tools and splashing water, not by air. So yes sanitizing your tools and removing the infected foliage is almost the only possible way to limit its spread. Does it work? I don't know, simply because I would have a hard time distinguishing bacterial and fungal leaf spot from each other.

For fungal leaf spot I think the best you can hope for is to limit it a bit. Certainly it works to some extent when you transplant as you then both move it to a new location and cut the leaf tips. The foliage is definitely healthier after transplant.
Name: Jan Wax
Mendocino County, N. CA (Zone 9a)
I'm a studio potter.
Hummingbirder Dog Lover Irises Region: California Organic Gardener Dahlias
Garden Art Cat Lover Vegetable Grower Birds Celebrating Gardening: 2015
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janwax
Feb 16, 2018 5:00 PM CST
I took care to trim back any emerging signs of leaf spot when I started
my cleanup about a month ago. I've also thinly spread some lime because of a hint from Barry Blyth in a catalog a few years back.He recommended it for leaf spot. My soil can use the extra lime because it tends to be acidic - because of the redwood forest.
Just wondering...would hand sanitizer gel work as well as bleach?
VOTE!
[Last edited by janwax - Feb 16, 2018 5:01 PM (+)]
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Sweden
Bulbs Lilies Bee Lover Irises Hellebores Deer
Celebrating Gardening: 2015 Photo Contest Winner: 2016
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William
Feb 16, 2018 6:36 PM CST
Jan, I think this depends on both how you use them and what you are targeting. Some disinfectants work better for certain pathogens than others. Sorry I can't really be more specific than that, as I'm not an expert. It's also about time, as longer disinfection time is better than shorter, generally speaking.

Also Lysol all purpose cleaner is well know for use against virus(but I haven't tried it as it isn't available here) and even milk has anti viral properties, but I don't know how these are against fungi and bacteria, which perhaps is the bigger threat here.

Virkon S would also be a really solid choice, probably the best actually. All these do work best as long as the tool is clean from sap... which brings me to the other option, simply use several cutting tools, one for every plant and then wash them, just as you would wash your dishes.

None of these methods are however 100% effective, if you want that you need to flame your tools, that is submerge them in alcohol and put them on fire, but this is too much work for me in most cases. This is a method that for instance can be used in tissue culture propagation.

I wish you good luck with the lime application. I do sprinkle a bit of wood ash around my irises during winter, which is similar, but I have not seen any certain results of that so far. I do sometimes use a bit of wood ash on Hellebore's against Botrytis and also I've seen it recommended for the same purpose on lilies, so probably it has some effect as to avoid spores to splash up with soil on the plants when its raining.
Name: Jane H.
Kentucky (Zone 6b)
Irises Birds Region: United States of America Region: Kentucky Clematis
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janielouy
Feb 16, 2018 7:38 PM CST
I have heard that lime is also good for "trying" to get rid of moss although our hot summers do a good job eventually. Lysol all purpose cleaner is cheap and so is bleach so there are two options. Wood ashes are supposed to be good for daffodils too.
Name: Leslie
Durham, NC (Zone 8a)
Region: North Carolina Irises Cat Lover Garden Photography Enjoys or suffers hot summers Celebrating Gardening: 2015
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Lestv
Feb 16, 2018 9:12 PM CST
Lime is used extensively in the south to rid lawns of moss. Changing the Ph really does a number on the moss. Moss is a big problem in shady areas around here. Unfortunately I have quite a bit of moss in the lawn near my JI beds that can't be limed.
My road calls me, lures me west, east, south & north; most roads lead men homewards, my road leads me forth. - John Masefield
Name: Dirt
(Zone 5b)
Plant Lover: Loves 'em all! Garden Photography Bee Lover Region: Utah Photo Contest Winner: 2014 Celebrating Gardening: 2015
Photo Contest Winner: 2015 Photo Contest Winner: 2016 Million Pollinator Garden Challenge
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dirtdorphins
Feb 16, 2018 10:18 PM CST
Sorry, I don't have any advice--I just pull off most of the dead, crispy leaves in the spring, ... and some of the half-dead ones and live ones too, but not on purpose

Mostly, I wanted to say, I think moss is cool and I have tried, but, I can't keep it alive Hilarious! can't do JI either or blueberries or oriental lilies or Sighing! very alkaline desert thing going on over here
Name: Ian McBeth
Lincoln NE (Zone 5b)
Plant Lover: Loves 'em all! Amaryllis
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SonoveShakespeare
Feb 17, 2018 11:48 AM CST
I hate it when I have leaf spots on my irises too. One year I had a patch that was full of irises that I forgot about. Over the years, that patch got so crouded and full of grass/weeds that when I cleaned up the bed (pulling the weeds) I noticed that the ground (dirt) in that patch was severely crakced. This meant that the irises barely got any water and I also noticed that the majority of the irises had leaf spot really bad. Some of the leaves were brown almost halfway down to the rhizomes (and few were still pretty green). I don't know how some of them (the green ones) could've survived that hot and dreadful summer without hardly any water. But they did. Blinking I eventually got so frusterated dividing them and cleaning out the patch that I threw some in the trash. I regret it now because some of them were ones I really liked. Crying I will never abandon any iris patch of mine again because I learned the hard way.

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