Q: Removing one turfgrass from another is a tough assignment. Digging is one option but it is hard work. If you use a chemical, how will a herbicide tell one from the other? Here is one way:
Q: I seeded my back yard with ‘Zenith’ zoysiagrass this spring. I have found a few small patches of bermudagrass in the middle of the zoysiagrass. Is there a way to get rid of the bermudagrass without hurting the zoysiagrass?
A: According to UGA weed specialist Tim Murphy, one option is to spray bermudagrass three times, at four week intervals, with glyphosate (click for sources) in order to kill it. If you start spraying in mid-summer, you won’t have time to plant seed before winter. Start the sequence next spring when you first notice the bermudagrass spots. You can then plant ‘Zenith’ in mid-summer.
Suppressing the bermudagrass is another tactic to try. Mow your zoysia a bit higher than usual: 2″. The increased shade decreases bermuda growth. Remember to fertilize sparingly. Dr. Tim Bowyer, retired zoysiagrass expert, says he gets a great-looking lawn by fertilizing only twice per year with Milorganite.
BTW: I note that the label on Weed B Gon Chickweed, Clover and Oxalis Killer(tm) states that the chemical causes damage to bermudagrass but is tolerated by zoysiagrass. If you are content to chemically suppress the bermudagrass, try to “find” a clover plant in the bermudagrass and spray it at four week intervals with the product mentioned.