Howdy! Now that I know I'm dealing with rot and not borers, what is the advise for planting irises where the rhizomes grow "vertically"? Pic attached of a few examples.

I actually received quite a few this week that look like this. I'm tempting to plant them as-is. My instinct is telling me the rot would be worse if I try and clean them up. Thoughts?

Side note from the borer string...

As I was cleaning the rot from the irises, I noticed the ones ordered last year were showing no signs of rot. They were planted using only the soilless mix, no soil conditioner was added. (Probably because I ran out.) So I went through all containers and adjusted so the top 3" is soilless mix only. We've had rain almost every day this week and so far so good. I only found one soft spot and cut it out and treated with bleach.

Casey - I frequently get "vertical" rhizomes, too, and am never sure how to deal with them. Plant them so the rhizome is parallel to the ground level but the leaves stick straight back? or plant them vertically so the leaves stand up straight? I've followed the latter approach, but doubtless I lose some of the increases that get buried.

I think your idea of using soilless mix for the top 3" is brilliant, by the way. I shall keep it in mind for next year.

Andrea and Casey ~ Mary at Bluebird Haven Iris Gardens says not to worry if the rhizomes are covered with an inch of soil. She does, however, recommend that we plant the irises with the leaves upright, not leaning either way.

She instructs me each time I come to pick up my orders..."Be sure to plant them upright!"

I just noticed something when I was inspecting some irises today. There was some small leaves that had rot but the larger rhizome was fine and clean, even though partially buried. I just tossed the smaller ones into my garbage bag, (Not for compost.) and left the other parts in place.

evelyninthegarden said:Andrea and Casey ~ Mary at Bluebird Haven Iris Gardens says not to worry if the rhizomes are covered with an inch of soil. She does, however, recommend that we plant the irises with the leaves upright, not leaning either way.

She instructs me each time I come to pick up my orders..."Be sure to plant them upright!"

Evelyn, Thank you for the recommendation about planting the rhizome with the leaves upright. That is helpful.

Thank you Andrea and Evelyn!!! Looks like there are a few I planted last weekend that need adjusting. Ha! Now we know.

Andrea, I'll let you know how they all do topped with the soilless mix. I thought it would help adding soil conditioner, but maybe that was too much against the rhizomes.

Just curious; what were you using for soil conditioner?

I believe it's also called pine fines. I use it in the beds as mulch to help with weeds and keep the soil from drying out too quickly...

And as I write this, I think I know where I went wrong!

I was mixing about 1/4 soil conditioner with 3/4 soilless mix, and sometimes adding plain potting soil when I could find it. (No fertilizer or moisture control.) When I repotted them, I used that mix in the bottom 2" of the pot, then added 2" of Daddy Pete's Raised Bed Mix, and topped the rest with the soilless mix. So I'm probably closer to 4" of the soilless.

Someone had mentioned the roots want moisture, but the rhizomes don't, and I thought the layering made sense. Daddy Pete's is a mix of gypsum, sand, pine fines, perlite (which is great!) and aged cow manure (which is risky) but I'm not using a lot. I'm keeping an eye on them and so far so good. And with all the rain coming, we've made room in the garage for them to ride out the storm. William mentioned keeping excess rain off helps with the rot issues too.

Your "vertical" rhizomes tell me that they are trying to "grow to the correct depth". The "mother" is "too deep", and the "daughters " are trying to get up to the soil surface.

Thank you Arlyn! I've received rhizomes that dip down a little, but the ones I received this week look like elephant trunks! (The ones on the left especially.) I was a bit perplexed as to how to plant them, but knew someone here would have the answer!!

I received some new rhizomes from Suttons today, big fat, healthy looking rhizomes, but almost all looked like they were formed with a built in spike to drive them in the ground. I have never had any like that, but planted them upright. I was not sure either. I do like the idea of soil less mix to top.

Hi Nancy! Mine came from Sutton's too. And one or two from Schriener's. I hadn't seen that either!

What is soilless mix called? I have never heard of that. I have used seed starter but don't think that is what you mean.

Jane, I use Sungro Horticulture Professional Grow Mix. I buy it from a greenhouse around the corner from me. It's a mix of peat moss, composted pine bark, vermiculite, dolomite, perlite, lime and a wetting agent. (Not sure about that, but it's the last ingredient.) Pic below.

It's a little more expensive than potting soil but a lot lighter and drains well. Maybe it was a fluke last year's purchases didn't rot or maybe it's due to this mix.

This year will be the test. In fact, the next few days may be the test! It's been overcast since dawn and the winds have been increasing all day, but rain is really the threat for us. Earlier this week we we're looking at 2-4" rain, and now they're predicting over 10". Nothing like the coast, but's it's still a lot of rain! I'm going to wait a few more hours then start moving all the containers of irises into the garage. That's should work - as long as the garage doesn't take on water!

Good luck, Casey!

Thank you Andrea!

I saw a lot of green growth on the rescues, which is encouraging. A little over 100 containers, and most containers have multiple rhizomes since they're so small. It would be awesome to save those, lots of favorites.

I've been meaning to ask you... what iris is your profile pic? It's lovely!!

Casey, my profile pic is Better than Butter (Black 2010). I recommend it highly. It is a ferocious grower, very floriferous, and blooms for a long time. It was a runner up this year for the Wister Medal.

AndreaD said:Good luck, Casey!

Yes, please take care!

Wow, what a great review! Thank you!! It's been added to next year's wish list.

And thank you Andrea and Evelyn for the well wishes! So far, so good.

Here's hoping it stays that way!