THE TRUE MEANING OF WINTER MULCH

From the questions I’ve been getting, I can tell there’s a lot of confusion about the real reason we mulch in winter. As tempting as it is to think that we’re tucking our cherished perennials under a cozy blanket of mulch to keep them warm through the Big Chill, that’s not the case at all.

Our plants don’t need protection from the cold. After all, the perennials in our gardens are hardy for our winters – that’s why we plant them. They require the period of dormancy that comes with the cold. By the way, it generally takes two or three hard freezes for plants to become fully dormant.

No, what our plants need protection from is the cycle of freezing and thawing that temperature fluctuations bring. These shifts can heave perennials from the ground and expose their roots and crowns to fatal damage when the weather turns cold again. That’s why we actually cover perennials with mulch in winter, unlike in summer when we spread the stuff around plants, but not on them. Summer mulch is another matter. But there’s plenty of time before we have to talk about that.

So, contrary to popular belief and maybe even logic, winter mulch is not intended to insulate plants from the cold. The true meaning of winter mulch is to hold in the cold.

Which is why you shouldn’t put it down too early – if the soil’s not cold, the mulch will only foster fungus and diseases. Besides, voles and mice and other creatures may still be on the lookout for warm winter digs. And if you mulch too soon, you won’t just be providing them with housing, you’ll be providing them with food as well.

And despite last weekend’s storm, you really can’t rely on snow – AKA “the poor man’s mulch” – to take care of things. In our parts, we just don’t get that much of it anymore. I mean, think back to when you were a kid – there was snow on the ground practically all winter long. Now that the white stuff has melted, tuck in any perennials that might have pushed out of the muddy muck. But don’t be fooled, it will get cold again. So cut a few branches off your Christmas tree and lay them over the garden beds. You'll be helping your perennials chill out.