Does anyone have any ideas on how to get rid of weeds in irises on a large scale? We have a field about an acre in size and need to get rid of a very bad weed problem and then keep them weed free!!
Some iris growers use solarization each time they divide the irises. The plastic is expensive and difficult to recycle, though. And it depends on your growing zone. What zone are you in?
Many people use a pre-emergent herbicide called Preen. I have never used it. You must clear the weeds first, then apply the Preen to prevent new weeds from sprouting.
If you have irises in straight rows, you can put down thick sheets of newspaper and cardboard between the raised rows and cover it with mulch. You still have to weed between the irises, though.
Do not use glyphosphate or Round-Up around irises. They are extremely sensitive to it. Even a little waft of wind can ruin the iris blooms for a year or two and stunt the plant.
Thanks for your quick reply. The irises are in South Africa but we currently live in Zambia and are doing all of this by 'remote control'. we have taken over a very run down plot that has a lot of plants in the ground but lots of weeds too!! we are going to spend the next couple of years lifting, divinding, sorting etc. at present they are in rows but we are thinking about planting in beds instead as the rows have become a little strung out and the total area to maintain is too large.