Plants that are mulched before they have properly hardened are actually more subject to winter injury. In northern Iowa, strawberries are normally mulched in late October to early November. In windy, exposed sites, straw mulches can be kept in place by placing boards or wire fencing over the area. The fencing can be held in place with bricks or other heavy objects. Alternate freezing and thawing of the soil during the winter months can heave plants out of the ground and cause severe damage or even death.
Damage is most severe in poorly drained soils.
Gardeners can increase the odds of their mums surviving the winter by protecting them in the fall. Mulches should be applied in late fall after the plants have been exposed to cold temperatures, typically mid-November in central Iowa. Do not cut chrysanthemums back in the fall. While cutting mums back in the fall is a common practice, recent research found that unpruned plants survived the winter better than those pruned in the fall. Simply place several inches of mulch around the mums in the fall.