We advocate mulching around the base of your plants all year round but it’s even more important in the winter.
Mulch moderates soil temperatures, reducing the impact of temperature swings on plant roots. These swings are year round considerations. In spring, summer and fall, however, temperature swings aren’t as significant as they are in winter. They fluctuate only a few degrees in a 24 hour period. In winter, that fluctuation can be much greater and plant roots don’t like these wide temperature changes, especially those that drop from warm to below freezing.
Plenty of organic mulch like wood chips will minimize the effect of temperature extremes on your plants. During the spring, summer and fall, two to a maximum of three inches of mulch are sufficient. Any more is too much. In winter, however, three or four inches are preferable.
As you prepare your yard for winter, start by fluffing up the mulch already in place. Using a leaf rake, fluff it up similar to the way you would mashed potatoes or rice. Once the existing mulch is fluffed, you can measure its depth with a yardstick. Add enough new mulch to bring the depth to four inches; no more. Moisture still has to soak through the mulch to reach the plant roots. And, remember – don’t pile the mulch up against the tree trunk. As I’ve mentioned a number of times, that traps moisture between the bark and the mulch and provides a good breeding ground for microbes. It also helps camouflage small mammals that may want to dine on the bark.
Remember to remove any mulch over three inches in the spring. Look at mulching like placing a coat on the root zone of your plants. In winter, you need a heavier coat; in spring, a lighter coat will do fine.
I specified organic mulch because it does double duty. Besides protecting your roots in the cold weather, wood chips and other organic mulches will decompose and return nutrients to the soil. Decorative mulches like stone won’t do that. It doesn’t decompose. Besides, stone mulch is cold to the touch so it won’t moderate the soil temperature as effectively as wood.
If you don’t care for shoveling, hauling and spreading mulch, we have landscape professionals who would be happy to do these jobs for you before winter settles in.
For us, mulching is more important in summer. We do not get serious frost here, but the soil can get warm. Also, we like to keep the moisture in of course.