How do I control grasses in my iris bed?
Annual grasses, such as crabgrass and foxtail, can be controlled by hand pulling.
Perennial grasses, such as quackgrass, are much more difficult to control as they spread via underground stems or rhizomes. (All of the rhizomes must be completely destroyed to control quackgrass.)
When confronted with an iris bed infested with quackgrass, one option is to dig up the irises in July or August and replant them in a different (weed-free) location. Another option is to dig up the irises in July or August, set the irises in a shady location, and then dig up the grass and carefully remove the rhizomes and other plant parts. Dig up the area 2 or 3 times over a 3 to 4 week period, each time removing any rhizomes visible in the soil. Replant the irises in their original location after thorough eradication efforts. Quackgrass cannot be controlled by hand pulling. Herbicides are not a practical control measure for home gardeners.