Wait until the late winter or very early spring to prune the zebra grass, after all forecasts of frost have passed.
Don gardening gloves and hold back the grass blades. Peer down into the center of the plant to determine if new green blades have emerged from the ground. If there are green blades, take note of their height and do not cut the dead foliage back farther than the tops of the green blades.
Place a ruler or tape measure at the base of the plant and measure up to 3 or 4 inches above the ground, or taller if green blades are present. Cut off two or three blades using hand pruners to mark the proper height.
Cut the remaining dead blades off at the same height using pruning shears to cut straight across the top. Use the first few cut blades as a guide for the proper height.
Rake up the trimmed-off zebra grass blades using your hands or a rake and carry them to the trash can or to a composting area.