Boring Irises

Did that title draw you in? Did you think to yourself, "Irises, boring?? How can that be?" Well, it's not what you think. I love Irises and to me, they're anything but boring. I do like some better than others, but they each have their endearing qualities, not the least of which is their colors and they way they're dispersed on the blooms.

But I'm not the only one who loves Irises.

This year, I'm waging all-out war on a not-so-little pest called Macronoctua onusta - Iris borer. I suspected them last year, but hadn't actually found one. This year, a couple of my Irises needed dividing, so I dug them up and it was then that I came face-to-face with the worm.

In years past, I recalled pulling center leaves out of the fans because they'd turned yellow. They came out easily and I did suspect that something was causing this, but it didn't happen often and it didn't seem to be harming the Iris a whole lot, so I didn't do anything. Therein lies my grave mistake.

The borer lays eggs in the leaves, where they hibernate all winter. In the spring, they hatch and the caterpillars (much too nice of a word for these disgusting things) work their way down the leaves into the rhizomes, where they gorge themselves on the heart of your Irises. The result is a mushy rhizome and usually death of that particular part of an Iris clump. And what's worse, they like Siberian and Japanese Irises too, as well as Blackberry Lilies (Belamcanda chinensis). Ask me how I know.

That's the Reader's Digest version of the Iris borer story. For a great detailed tutorial of what to do about this problem, visit The Renegade Gardener's page, Iris Borer Alert!



Tonight, I found yet another Iris that's been attacked by the borer. My 'Edith Wolford' had a fan lying on the ground, so I investigated and found a mushy rhizome. I dug it up and there it was - the Queen Mother of all borers:


It was two inches long and a disgusting shade of flesh-colored pink. The previous ones I'd found were smaller and white. I suspect the rest of the plant is infected, so when I have more time this week, I'll dig the entire thing up (as I did the others that were infected) and check them.

I called Romie out to the driveway to see what I'd found and he took one look at it and sighed, "It's always something..." Yes, it is, and while this shows the unpleasant side of gardening, I like to remember its better side:

'Edith Wolford'


'Princess Caroline de Monaco'


Unknown cultivar


'Red at Night'


'Immortality'


Helen's Iris