Iris turning to mush! Why?

The varieties of bearded iris I planted last year started coming up along with the bearded iris that were here when we bought the house, but today I noticed the green shoots had a weird brown tinge to them. I figured it was rot and when I pulled on the shoot the whole thing came off easily and revealed a slimy secret. Parts of the rhizome also felt soft, but other parts were as firm as ever. What's the deal? They aren't planted any differently than those I inherited so why are mine turning to mush after looking like they were going to do so well? They are in a raised bed heavy in compost, so while the soil has a tendency to stay moist, it's not waterlogged or anything. And we haven't had much precipitation in quite some time.

The Iris likes shallow soil situations, they prefer the tuber to sit only JUST under the soil, and the sun to bake the tubers, this is called ripening the tubers and they will flower, IF buried too deep, they give out greenery but less or no flowers.

Soil that's often very wet will cause rot to set in, I would be adding a load of fine grit to open up the wet soil and allow air into it and to help with drainage, you never said how much sun or light you get on the area where the Iris are growing, IF not enough sun / light, that could cause a problem re drainage.

You mentioned you had already had the same type of iris growing in the same area when you moved in so is it maybe that you have changed the soil structure that helps to retain moisture rather than having free draining soil. I know they like well fed so I always add some Blood / Fish / Bonemeal to mix at the correct dosage per foot, this is a slow release natural feed, you can buy this already mixed in a box / bag from garden store.

I would also dig up the squishy tubers, look at the whole tuber and on the underside, make a cut to see if there are any little worms (they feed on rotting tubers / bulbs) lay eggs and a new generation feed on the tubers, IF none show up, then cut away ALL the mushy stuff, allow the good part to dry off on newspaper, go to garden store and but a powder for dressing tubers, this stops the rot and helps the plant recover. Here we call it Flowers of sulphur but the store may recomend something else.

Hope this helps you out a bit and you can once again enjoy those lovely flowering Plants.
Kindest Regards.
WeeNel.

Flowers of sulfur may be sold as dusting sulfur.

Thanks everyone! I have some work to do!

Thanks Diana, it's getting harder and harder to keep track of gardening products these days, they keep adding stuff and removing others, so annoying when you have used these products from time to time and with care, they are OK. Anyway I blame the EU, LOL, well you Gotta blame something EH !!!
Have a great Garden season.
Best Regards, WeeNel.

I remember a lot of the old names, and have been in the trade long enough to know how they are labeled on this side of the pond.
Over here we can blame the EPA- Environmental Protection Agency.