I'll be planting several hundred iris rhizomes in 2021 as I plan to launch a commercial iris business in the next two or three years. One of my greatest concerns is weed and grass control in my iris rows. Mostly, the time required to stay ahead of annual and perennial weeds.
I have planted winter rye as a winter cover crop on the ground I'll be planting this year. I'll turn that in later this Spring, then plant a follow up cover crop of brassica (mustard). I'll turn the mustard under before it goes to seed.
At that point I intend to build slightly raised beds, 30" wide by 50' long. I'll install drip irrigation on those raised beds and cover them with 2 mil. clear plastic to solarize the soil for six to eight weeks before the rhizomes begin to arrive for planting. This drip irrigation, under the plastic, should allow me to keep the soil sufficiently moist for the solarization to work and the brassica should provide a bit of fumigation as well.
I hope this will reduce the viable weed bank but I still want to find a way to minimize hand weeding. That means either a pre-emergent, applied immediately after planting the rhizomes, or some kind of over-the-top post-emergent herbicide.
My soil is a loamy sand. Excellent for irises. I'm located on 40 acres in a very isolated area. Nearest neighbors are five miles or more away. Also, a very dry climate. No risk of contamination by run-off.
What pre-emergents or post emergents have you used on your irises? What kind of results have you experienced?
Thank you for your time!
Sincerely,
Randy Smith
Southwest Kansas
Zone 5
