What is needed for winter kill on hybrid Bermuda? I have found 3 consecutive days with single digit lows will cause significant death on hybrid Bermuda in two situations. If mowing height is one inch or lower or if an area gets lots of traffic, like between hash marks on football field.. The best case for preventing this is hopefully you applied potassium before the plant went dormant. Having at least an inch of snow cover prior to the temperature drops will also reduce winter kill significantly. zoysia can also experience winter kill, but has better cold tolerance than hybrid Bermuda, Common Bermuda is very hardy, so winter kill is rare on common!