Time to chill out on winter mulching.

Byline: Paul Rogers 

COLUMN: Your gardening answers

The days and nights are turning cool. It must be time to lay down winter mulch on the perennials.

Wrong! Never, ever apply a winter mulch this early in the season.

Why the concern? Is it not one of the tasks of mulches to keep the soil warm? Do we not wish the soil to remain warm so that the roots of perennials will keep growing?

The function of a winter mulch is not to keep the soil warm, but to keep it cold once it freezes. Nothing that we can do will prevent the ground from freezing during a New England winter, nor do we wish to. Many perennials, including trees, need exposure to cold temperatures to ready themselves for flowering next year.

Winter mulch is applied to keep frozen ground frozen. The mulch protects plants from exposure to cycles of freezing and thawing that heave plants and break roots.

We need to allow plants to slowly freeze. Doing so allows them to do what is natural - chill down into a steady dormant state for the winter.

If mulch is applied too early, chilling is retarded, and that creates conditions for rodents to exploit. Covering the ground before the soil has frozen a half-inch deep allows field mice to set up housekeeping under the mulch.

Clean up the garden, but delay mulching until several hard frosts have forced rodents into their winter quarters elsewhere.

Winter damage to plants occurs in January, February and perhaps March.

Do not hurry the mulching.