Although blueberries are hardier than other fruits in cold weather, they are still at risk during a freeze. When a severe cold occurs, the cells in your blueberry bushes freeze, which causes them to rupture and destroy parts of the plant that produce the berries. Bushes that prematurely produce floral buds during the cold are especially susceptible to frosts.
Plant your blueberry bushes in a location that has the highest elevation you can and, if possible, does not go below 28 degrees Fahrenheit. Damage can occur below this temperature rating, but a higher planting spot is usually two to four degrees warmer than surrounding areas.
Remove any weeds that appear in the soil underneath your blueberry bushes. A clean soil that is firm and moist encourages a warmer climate that helps protect against freezes.
Place a plant cover over the tops of your blueberry bushes in midafternoon on days when the lowest temperatures are expected. Covers offer a barrier that help keep the bushes several degrees warmer than they would be on their own. Remove the plant cover once the freeze is over.
Water your blueberry bushes more when a freeze is expected. The additional hydration allows the soil to soak up more heat during the day and deliver to this to the bush for cold protection.
Prune your blueberry bush immediately after a harvest. This practice encourages bushes to fruit one to two weeks later than it normally would and potentially miss future freezes.