Question of the Week: December 19, 2019

“How important is mulching for my plants in the winter?”

As I mentioned, mulching is always a good plan. Mulches do so much to improve life for our plants. But specifically in winter, how important are mulches here in the Lone Star State?

Finely ground pine bark mulch lays flat and looks natural, as seen from the our own landscape.

Reasons we apply mulches…
Here are just some of the reasons we apply mulches to our landscapes and gardens.

Slow growth of weeds. Yes, weeds do grow in the winter. Cool-season weeds can be unsightly. Chief among them in beds: annual bluegrass, clover, chickweed. Mulches stop germination of these weeds’ seeds, slow growth of the plants, but only if they’re applied a couple of inches deep.

Continued Below

Moderate rate of change of soil temperatures (the freeze/thaw cycles). Aha. This is a big one in winter. If you have plants that are vulnerable to cold injury in your area, especially types that die to the ground and then must return from their roots, mulching can help ensure that the roots will survive to come back for another year. Here you’ll want to apply 2 to 3 inches of a fairly loose mulch such as bark or shredded tree leaves. But you probably won’t have to cover your plants completely (as, for example, gardeners have to cover strawberries up in the North).

Slow the drying process by limiting soil-to-air contact. Even in winter our Texas soils dry out. And watering can be challenging when it’s cold. Mulches can lighten that need.

Back walk in the Sperry landscape features river rock mulch to the left to slow the flow of runoff. Pine bark mulch shows to the right.

Lessen erosion by slowing flow of runoff. In this case you’ll need a fairly heavyweight mulch. A small size of river rock can be decorative and functional. I use bark mulch in our landscape, and I have to confess that I have to replace it following heavy rains. I can rake and retrieve some of it, but some always gets hung up in the groundcovers. In my areas of heavier wash, I go with the river rock.

Reduce splashing of rainfall and irrigation, thereby lessening staining of the side of the house and splattering of water-borne funguses. This is really critical if you have a light-colored house and red, iron-rich soil. It’s also critical if you’re growing plants like pansies or snapdragons that are susceptible to soil-borne water-mold funguses that splash up onto leaves and stems when it rains. Mulches help.

Improve looks of the landscape. Forget all the rest. This is why many of us put mulches out in our gardens. They just look good. After all, that’s a big part of why we landscape in the first place.

Horticulturists refer to these as “mulch volcanoes.” Odds are that there is a pile of soil that came out of that hole when the tree was planted. Rather than toting the unneeded soil offsite, the crew just piled it up around the trunk and concealed it with mulch. This is not a good plan!
Posted by Neil Sperry
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