After the hole has been filled in, firmly press down on the soil around the base of the plant. This helps remove air pockets and makes the plant more stable. Plants that are divided in late fall when the ground is freezing should also be mulched.
Once the hole is filled in, firmly press down on the soil surrounding the plant's base to remove any air pockets and enhance stability.  Plants that have been divided in late fall when the ground is frozen should also be covered with mulch.