Benefits of Laying Mulch in Winter
Mulch in the garden helps protect the soil in general, but offers certain benefits in harsh winter conditions. A layer of mulch will keep the soil isolated, the roots will be protected from freezing or overly damp soil, and you will also get better results in the spring by laying mulch in the colder months.
Chris Weatherby, writing for The Oregonian, explains the benefits in more detail:
Autumn and winter mulch create an insulating barrier between soil and air, thereby protecting plant roots from sudden fluctuations in soil temperature. Changes in temperature create movement that can pull plants out of the soil, exposing their crown or upper root system to dangerous frosts. Autumn and winter mulch also protects the soil from soil erosion and compaction from heavy rainfall.
You can also use mulch in the winter to line unpaved paths that turn to mud during the rainy season. Different types of mulch (shredded leaves, wood chips, straw) are best used in different areas of your garden, and the complete guide below explains where to use which type of mulch.
What You Need to Know About Winter Mulch | Oregon Live