I have a gardening book that says in the garden calendar that in March I should burn over the iris bed, but it gives no reason, or instructions at all. Has anyone ever heard of this? Is it outdated info or what?
Regarding tall bearded irises, I think the only use that would serve is to remove any dead foliage or rhizomes. I prefer to use my two hands - they still work pretty well, and are usually less prone to setting the neighborhood on fire. :-)
Don't think you are the only one that has heard of this... http://davesgarden.com/forums/t/695896/ of course I don't think this burn was intended for the iris bed. In our area, the gardeners think it adds to the soil to burn it off. I am highly uncomfortable with this treatment as I live "in the woods". Therefore, I agree with Nifty and would say please don't strike the match... : )) pod
I just joined a local Iris society. At a meeting a couple of months ago, they described "burning off". It is used in the late fall or very early spring to remove the spent foilage. It's more widely used in the small towns or outside city limits because we can't burn in the city. Most of the growers used a hand held torch type of device to do the burn and kept it a few inches above the ground. If you choose this method, make sure you have a burn permit and the wind is calm.
The other method is to trim off the foilage by hand. Some shear it down to the ground, others leave about 6 inches. We were told the trimming should be done by March 15th but I would guess that's related to the zone you're in. There were a few people that mow their iris beds at the end of the season rather than clip by hand. It depends on how large your beds are and where you live.