Mix up a herbicide that has the active ingredient sethoxydim in the early spring with the Bermuda grass is less than 6 inches in height. Follow the directions on the label when mixing up the herbicide and pouring into a sprayer. Selective herbicides that contain sethoxydim chemically target Bermuda grass without harming zoysia.
Walk across your lawn on a dry and wind free day and spray your Bermuda grass patches. Bermuda grass often grows seven spikelike branches on top of the stem, while zoysia grass has smooth stems with one spiky branch.
Reapply your herbicide in a few days or according to the directions. Till through the bare patches in a few weeks to prepare the soil for planting zoysia grass sprigs.
Apply a starter fertilizer over the bare patches that has an NPK amount of 1-2-1. Plant you zoysia grass sprigs 2 inches apart and 6 inches in between rows. By growing zoysia grass over the bare areas, you help prevent the Bermuda grass seeds from germinating and taking over those areas.
Water the area thoroughly. Place a clear plastic tarp over the sprigs to help the sprigs establish. Remove the plastic tarp off after a two weeks.