fall cut back on iris?

We always cut back siberian foliage in early Oct. as it makes such a mat. I have a serrated tool known as a Japanese rice knife. It scares the dickens out of me. Hold the foliage upright with my left hand and one "swish" cuts it. Much faster than sizzors, and if there are several yrs. of foliage it is impossible to use them. If siberian foliage turns yellow and pulls out easily there can be borer and the entire patch must be dug and replanted. Versicolor was the natural food of borers, but you can't blame them for preferring the big bearded rhizomes.

Interesting about the versicolors and the borers.

I would like one of those Japanese rice knives! They sound very fun.

Thanks for the info, too.

Here's some info about controlling iris borers for those who are a little leary about using insectcides. It's another great article from the folks at the Canadian Iris Society.

www.cdn-iris.ca/borer.html

Good Luck... Dan

That's a great link, zacattack! Lots of good iris borer info there!

Thanks Tabasco... I hoped it helped.

Some of you are interested in why imidacloprid may have been banned in New York. Besides it's apparent effect on honeybees (as mentioned in the link provided by jenhillphoto) it seems it could easily cause long term problems to many other forms of life. Luckily, I've not experienced problems with iris borers or I might view this a little differently, but as an advocate for organic gardening, I urge everyone to look for alternatives to chemicals or use them cautiously and only when absolutely necessary. Here's a couple more articles of interest.

www.pesticide.org/imidacloprid.pdf

www.moraybeekeepers.co.uk/N&Views/imidacloprid.htm

Dan

An early 20th century gardening bk. explains that the borer was a versicolor natural pest. When the plants were growing in marshes the insect could not get the rhizome under water. When people grew siberians nearby they were somewhat protected--when those plants were moved upland, whee iris borer. We have used the nematodes one time there were fewer borers, but we haver dug up the plants to see results. Some people talk about the idea of hybridizing for borer resistant plants; difficult to do on the west coast which seems to be free of them. The historic TB The Black Douglas seems resistant. At least when the tunnels were in the rhizome there was no rot, the tunnels were clean. Thank you for posting the article, can be very helpful.

Interesting article about the bees. Losses have been noted across the country & even made non=interesting TV news shows when they can't find anything else to say. Has the article been posted for bee keeper forums? Note about arsenate of lead in early article. Since I am on my knees when weeding & have asthma, I don't want anything to do with that stuff.

Yes. I will be very careful. Indiscriminate treatment is not a good thing. And I have and will try the more gentle approaches.

Bayer didn't explain why the chemical is banned but I didn't pursue it. I don't have the iris borer problem but wanted to know where to buy it in the event the dreaded lily beetle makes its way to Long Island since it seems to be headed this way from the northeast.

georgiacat We seem to have headed away from cutting leaves--we only cut the bearded way back when transplanting. Other times the leaves are taken off when showing brown or disease.

pirl The lily leaf beatle is indeed here. they are easy to spot as they are scarlett & they are quick to move when trying to catch them. Eggs are orange, don't know why they were not spotted unless plants were smuggled in. I have been told by an iris robin person in Denmark that while they eat different things they only lay the eggs on lilies and fritillaties. (sp?).

Thank you. I read a lot about them and have seen photos and warnings about how to catch them and how to look under the lily leaves. Come April I'll be on the lookout for them.

Dan, thanks for that link to the CIS site... I'll include it in the article. It's good to have a variety of options, especially when it comes to alternative organic controls. :-)