Looking for some help from the iris experts here...

I have a mixed perennial flower bed that includes a fair number of bearded iris and every year they develop brown spots on the leaves that pretty much progress until the affected leaves die. From what I've been able to find, this is caused by a fungus -- ? Any recommendations for what to use to control this problem? Thanks!

Good to see you on here Sandy, Thought you only grew tomatoes I have those fungal spots too every year, some years worse than others. I have never sprayed for them, and besides looking tacky, they haven't killed any of my irises. Others on here do spry for them, not sure how effective that is, but I'm sure that they will give some feedback on here. Good Luck!
P/S: I have started my tomato plants.

tveguy3 said:Good to see you on here Sandy, Thought you only grew tomatoes ...
P/S: I have started my tomato plants.

LOL, Tom -- that's why I need help with the irises! I will say they are pretty tough; I planted them quite a few years ago and they not only survive the fungus (or whatever it is) but also extreme neglect some years.

Good to "see" you !

Hi, Sandy. {{waving}}

Like Tom, I leave mine alone. By August, their foliage looks bad, anyway, from the heat and no rain, so a little more 'unattractive' goes unnoticed.

I think Arlyn sprays for leaf spot. He will know what products work best. @crowrita1

Hi Sandy-
Like Tom and Debra I feel about the same way. This year I was unable to get to it with some spray because of heavy, heavy rains all spring. So I already have brown leaf spot in almost all the iris gardens. Usually our hot July weather is the worst because of humidity. So I use two fungicides in all the gardens; onions, tomatoes, cucumbers and irises! The two I use are fairly natural products which I use alternately. Something else I do is to dust any iris rhizomes I send in the mail lightly with pure old natural garden sulfur. Just some thoughts.

Thanks, everyone! It sounds like I can stop feeling guilty about the spotty leaves... I do have some Daconil, though, so maybe I'll give that a try. And here I was thinking everyone else probably had pristine leaves on their iris all season long .

I might have to start lurking here -- not just to learn something useful, but because there seem to be quite a few members here that I never seem to "see" anymore!

Then you need to stick around, Sandy, and 'see' us often. And perhaps catch the iris virus.

I've tried spraying the iris with fungicide and found that the spray just rolls off the leaves and hasn't had much noticeable effect. Last year I also sprayed and the leaf spot wasn't as bad, but I'm thinking it might be because the rainfall wasn't nearly as bad last year as this past winter/spring. One iris farmer mentioned that a surfactant (ie. detergents, soaps) was needed to help allow the fungicide to adhere to the leaves. And as mentioned here already, although the leaves look unsightly, the plants typically suffer no significant harm.

grannysgarden said:Then you need to stick around, Sandy, and 'see' us often. And perhaps catch the iris virus.

Well, they ARE my favorite flower... I think you all might be seeing more of me than you want to .

"although the leaves look unsightly, the plants typically suffer no significant harm."

I guess mine will attest to that... some of them have been in the ground since 1991 and have managed to survive in spite of my negligence!

Seems to me that some cultivars get the spots more than others. One will bull of them, and a different one right next to it will be clean.

I totally concur with Tom's last post. In my 'line-up' of 16 along the driveway, Strawberry Shake and Orange Harvest are looking like 'leopard iris' with all the leaf spot and some next to them have a minimum amount of affected leaves. In that same vain, I found that some iris hybrids seem to be more susceptible to snail and slug attacks. In that same line-up; Adoree was being ravaged while only minor changes were noted in other pots nearby. A little late, but I did wage war and took measures to get those pests before the bloom spike got affected and fortunately the flowers turned out fine in my first year. I'll know better for following years to put extra snail bait in with the Adoree pot to protect it in late winter/ early spring.

Interesting! I have some of the very old-fashioned yellow iris (the kind that grow no matter what you do to them or where they are planted - or tossed); I'll have to pay attention and see if those are as affected as the more modern ones that are in my garden.

to the iris forum, Sandy!

And another to the iris forum.

Thank you!

I'm a little "late to the party", here, but I DO spray for leaf spot. As to the "product'....Daconil is one that I use, and there is one by Fertilome, that's "systemic", and one that's "broad spectrum" (has three different active ingredients), and I also use the "garden sulpher" (powder, mixes into water to create a "sprayable" ) if you've been counting...that's a total of four different fungicides. I *suggest* that you use at LEAST two different products, as fungi...as with bacteria...an *immunity* CAN develop, and you end up with "super spot" !
I spray (with a different product, each time, in rotation) on a 10 day-2 week schedule. As was mentioned , iris leaves are "glaucus" (waxy) and to help prevent run off. be sure to use a "sticker-spreader", added to the solution.....you can find it in the garden center, OR, you can use liquid dish soap , about 1 cap full to a gallon of water (and, if you use "anti bacterial" dish soap, that *might* Help with soft rot, too). Another thing that seems to help when spraying the fungicides (or anything else in the garden, for that matter!) is to spray when the plants are "clean"....i.e. after a rain, or early in the morning, when they are dew covered....the product will "spread out" , and" cling to the leaf' much better.
Begin spraying fungicide, as soon as new growth is 4"-6" tall (for the iris), and keep it up until late summer, or early fall ( I also use the same program for the peonies, and the garden phlox). After the spring bloom is done on the iris, I add, to that next spray product (whichever it happens to be in the rotation) Miracle Grow, mixed in at about 1/2 -- 3/4 the recommended rate per gallon. What this does , is cause a "rush" of new leaf growth....the plants will tend to "push off" all the old , tattered leaves, over the space of a couple weeks....makes them look a lot better, and gets rid of a lot of "spore" from the leaf spots that didn't get taken care of by the fungicides.
All that said.....the *best* two things you can do for fungal leaf spot(as well as several OTHER disease problems) is a reall good "clean up" at the end of the season....get all the 'trashy leaves "out of the garden...and into the trash can,NOT the compost pile! and secondly, allow enough "space" between plants to allow good air flow, and sunlight penetration.......the drier the leaves, the less fungus (and helps with soft rot, too !).
But, as was pointed out, it REALLY doesn't hurt the plants, all that much...they are hardy, and do quite well, even with less leaf area for photosysthesis . Some folks cut back the leaf fans...totally....after bloom is done, and, while the new, emerging growth DOES look better....I think a leaf that is 1/2 covered with leaf spot STILL produces more *energy* for the plant , than NO leaf does ! Plus, if you grow rebloomers....mid summer leaf removal will almost guarantee no rebloom !

Arlyn, thanks so much for the very comprehensive instructions -- I starred your post so I'll have some hope of finding it again! My iris are only about 5-6" tall right now (other than a few the deer have munched ), so it seems I asked my question at just the right time. And I have both the daconil and soil sulfur, so I'm good to go...

Now if the weather would just warm up here!

I wonder if a biofungicide like Serenade would work on iris leaf spot? https://www.groworganic.com/se... I guess I should try it.... a few of my irises are horror shows.

I agree with the observations that some of the irises are much worse than others, with regards to leaf spot.