Help: I've got a few iris rhizomes that are

getting soft. When I dug into one, I found many tiny white maggots. Are these iris borers or something else? They aren't eating the leaves, they're just in all that soft rhizome.

Thanks,
Vicki

No, those aren't borers. They're some other sort of opportunistic feeder attracted to the rotting flesh of the rhizome. You don't need to worry about the maggots, but it would be a good idea to try to figure out what caused the rot in the first place. Of course, pretty much anything that stresses an iris plant can leave it vulnerable to rot infection, particularly if the cultivar is especially rot-prone. Here are a few of the more common conditions that may promote rot:

Consistently damp soil - excessive rainfall or watering, or clayey soil that retains moisture and never dries out

Physical damage to the rhizome - insect, rodent, or foot traffic can damage a rhizome, leaving an opening for rot bacteria to enter

Excessive fertilization, esp. with nitrogen

Repeated freeze-thaw cycles, particularly in new plantings with insufficient root systems

But like I said, just about anything can promote rot in rot-prone cultivars. Sometimes the trick is to simply allow the rotters to die off and replace them with stronger cultivars with greater rot-resistance.

Good luck,

Laurie

Thanks very much Laurie.

These came from Waysides end of season sale and some didn't look that great to begin with. Out of probably 30, only 4-5 are like this. We've also had an extremely wet fall so it could be a combination of plants and rain.

If it was from damaged rhizomes, do you think that the smaller rhizomes, which have formed and leafed out on the sides of the large ones, will make it or will the whole thing rot?

If needed, I could break those off and replant, but it is getting so late, I may just wait and see what comes back in spring.

Thanks again, your wisdom is always very welcome : )

Vicki

In my experience, I have found that even when the primary fan rots completely, sometimes the small increases will survive and continue to mature. Then again, rot may invade the increases as well and take out the whole plant. If it were me, I'd leave them alone and hope for the best. I prefer to let Mother Nature weed the rotters out of my garden.

You might try contacting Wayside and see if they'll agree to replace the plants next year, since they didn't even make it through this growing season.

Laurie

Thanks : )

Laurie and I agree on most things b-u-t- this is what I would do.

I would haul them out, clean off the rot - in fact when you have dug out all the rot with a spoon or something, I would take a clean knife and cut off a bit more, just to be sure. Then rub well some ajax/comet/bon ami into the cut and replant in a diff. place. If it was me in zone 2/3 I would pot them up and under lights inside for the winter. If you don't have snow etc.in blissful zone 6 then plant them in the garden.

Make very sure that you disinfect your knife very well in javex or similare between cuts.

Also, whenever you receive rhz. or lilium from anywhere, it is a good idea to totally immerse them in a mixture of 1 or 2 parts javex to 10 parts water for half an hour or more. them rinse well before planting.

I guess I tend to do this because I cannot bear to lose a single rhz.

Ginny

Thanks Ginny! What is Javex, I'm guessing it is bleach?

LOL, we do have snow in "blissful" z 6 and ice and it even got down to -8F one morning last winter. I can imagine the challenges of gardening in your zone, I have zone envy up to about z 7, any more than that and it'd be too hot for me : )

I'm afraid we aren't going to dry out enough to dig up and replant, I was poking around this afternoon and it is a muddy mess out there and I don't have any room to keep them inside.

Seems like I've read about putting the ajax/comet onto the cleaned up parts, I'm going to have to print this so I can find it again. I've also seen the info on soaking various bulbs, tubers etc..in a bleach solution. LOL, I've read so much stuff this year alone that my brain is on overload. I've started printing important stuff like this to look back thru so that I don't forget it until somethings already been planted (like now)....thanks again for reminding me of those to tips! Printing them out now : )

Vicki

I think I would do the same thing inanda said,
and I've also heard that some people place a shovelful of sand on top of good rich soil and place the rhizomes on top of it to ensure the best drainage. I barely cover the rhizomes with soil because the drainage is
iffy in my garden.

I have heavy clay soil that likes to hold water & then dry hard as cement. I raise each clump 2-3 inches above the planting level of all the perennials around it to ensure better drainage. The raised clumps always dry more quickly than the plants around them.

Good idea, Wanda- I have the same type of soil. I can tell by all the gorgeous pics of your garden your method works well!

Thanks for the tip Wanda.....I've got most of mine in a bed by themselves, I want to incorporate them into my perennial beds next year when I expand and will use your method. I've got the old yucky clay too, amended with peat and whatever else I come across. I've got the tops of my rhizomes just above the soil line right now, I'm going to cover them with cedar limbs for the winter, since they are newly planted.