Guest Contributor
Erica Jones, Extension Master Gardner
Even though we are now freed from the mow-the-lawn and pull-the-weeds scramble, winter brings some fun things to do outside.
The activity that springs first to mind is pruning. Yes, winter is a fabulous time to do with (most of) the leaves off. I see so many people doing it in a fashion I think is wrong, I don’t want to wade into that swamp. If you want to learn it, beg a hands-on lesson from a knowledgeable gardener whose yard you like. The online video https://www.youtube.com/watch?v=rl7pHemVye8 , is pretty good. In a quick internet tour of pruning seminars, I saw mountains of bad pruning on display.
So, onto mulching. Mulching in the late fall/winter has a lot of benefits. You mulch for three main reasons: 1. Reduce weeds 2. Keep water in the soil 3. Keep the soil in place. Then there are the esthetic reasons for improving the looks of your yard with a nice, uniform-colored mulch. If you have kept up with the yard work enough this year to be worrying about looks at this point, give yourself a big mug of hot chocolate.
Winter mulches do help keep next spring’s weeds down. Annual weeds have been throwing seeds around in your yard all year. If you put a good layer of mulch over those seeds, they will have a much harder time germinating. For perennial weeds, mulch will at least slow them down, but not necessarily smother them. Well mulched weeds are easier to pull in the spring though, I think (never read a study on this though).
Keeping soil moisture in: Yes, plants in the winter need water, albeit a lot less when they are having to support foliage. Newly planted trees and shrubs should be mulched to reduce your winter watering chores if it gets dry. The place where you purchased trees and shrubs should have told you to keep them watered for 12 months after planting; which runs you into winter. Newly installed spring bulbs love a mulch too – again keeps the water in the soil and reduces weed competition. And there are some perennials which do well planted (and mulched) in the fall.
If you have never considered what bare soil will do all winter, think again. Remember learning about the dust bowl in school of the 1930’s? Well, bare, un-mulched soil will leave town in a high wind, but also leaves courtesy of runoff – when we get the heavy downpours like we have in the last couple of years. Mulch softens the impact of raindrops on the ground and adds, in effect, rainwater storage which will slowly seep into the ground. Not only do you get more water, its less pounding and compacting of the soil.
Winter mulch material should be something that is not going to blow around. Leaves make fabulous mulch, but they might need to be chopped up with the lawnmower to help them stay put. In theory, mulches will tax the nitrogen content of the soil underneath as the soil microbes that decompose that mulch will require some nitrogen. Fall/winter mulches are good in that nitrogen usage of plants during fall/winter is about zero. One of my favorite good-looking mulches is pine needles. These guys don’t form a surface ‘crust’ as easily as tree bark mulch does, and you could argue the lighter color blends into your landscape better.
Two other lighter-colored mulches are straw and old hay. Straw can be a little wiggly until it gets good and wet. Old hay varies in color quite a bit depending on how decomposed it is. If you put down a moderately thick layer (four inches), this should be enough to discourage most of the weed seeds which you will always find in hay. Six inches is even better.
One final benefit of mulches is that they keep soil temperatures and moisture content from fluctuating as much as it does in bare ground. The common advice for planting marginally winter hardy trees, shrubs and perennials for your growing area, is to mulch well in the fall. Sometimes a good winter mulch will allow you to grow a plant about ½ of a zone colder than where it is traditionally hardy.
Two mulches I do not recommend are landscape fabric and rock mulches. Landscape fabric is tough on your soil, keeping all organic matter out of your soil, and tends to repel rainfall. Organic matter helps the soil retain moisture, helps retain nutrients, and makes it easier for roots to travel through the soil. Rock mulches, to be successful, either require a layer of landscape fabric under them, or need to be put down very thickly (like four inches or more). That’s a lot of rock.
