Garden Mulch Tips From Area Experts

Garden Mulch Tips From Area Experts

When October rolls around, it’s time to think about putting the garden to bed for the winter. And part of that process includes picking appropriate mulch. Mulch serves different purposes for different garden uses and in different seasons.

In winter, for an empty, fallow vegetable garden, it helps prevent erosion and prepares the soil for next season’s crops. For shrubs, mulch helps prevent desiccation (when branches turn brown from extreme cold and dryness). Mulch also protects the crowns and surface roots of perennials and insulates the soil. It keeps the soil an even temperature so the sun won’t encourage premature new growth in the winter or too early in the spring.

Here are several mulches recommended by local garden experts and others. Consider your garden’s unique needs and your own personal preferences when choosing your mulch.

Leaf mulch: Olbrich Botanical Gardens has an annual leaf mulch sale on Saturdays in early October. The mulch is made from leaves collected by the City of Madison that are delivered to Olbrich. They’re composted, double shredded, and then ready for bulk purchase. Benefits of leaf mulch beyond those already mentioned include that it adds natural nutrients and improves soil structure, recycles local leaves and is a neutral pH product.

Pine straw: Glacierland Resource Conservation and Development published a feasibility study on the use of pine straw as a mulching/landscaping product. While it’s used more commonly in the southern U.S., pine straw is a readily available, often inexpensive mulching material in Wisconsin. The benefits of this mulch, according to the study, included that pine needles interlock and hold together during hard rains and heavy winds, even on sloping landscapes. The narrow, long needles allow moisture to flow through them to conserve soil moisture. 

Shredded wood mulch: UW–Extension research has shown that healthy shredded wood mulch can contribute to the health of landscape trees, including by limiting damage to the trunks from mowers and string trimmers. Some gardeners prefer the look of shredded wood mulch. Because it decomposes slowly, garden experts recommend checking soil nitrogen levels regularly if you use shredded wood mulch. You might need to amend with nitrogen fertilizer, but check to make sure.

Marsh hay: Becker Family Farm and some other local farms harvest marsh hay and bale it for local gardeners. Marsh hay is free of typical garden weed seeds that are often found in straw or hay. The blades of marsh grass have fine edges that interlock together, so they hold together on the ground. After an initial watering or rain, the mulch stays in place, even during strong winds. Marsh hay decomposes at a moderate rate and adds nutrients back to the soil.

Decorative stone: During the dry spring and summer of 2012, the Madison Fire Department responded to many fires that included smoldering mulch. While your mulch likely won’t catch fire during the winter, it’s something to think about when considering your investment. The fire department recommended that gardeners and landscapers consider replacing some landscaping mulch with decorative stone. In addition to the fact that it doesn’t burn, stone is a great mulch for rain gardens, where drainage and filtration are the goals. It does not, however, decompose or add nutrients to the soil.

Most of these mulching options are available at multiple locations around the city. Check with your local gardening supplier and expert for their recommendations and guidance for your unique needs.

Beth Stetenfeld is a McFarland-based editor, writer, master naturalist and creator of the gardening blog PlantPostings.com.