Shredded Mulch in Michigan: Natural Brown Hardwood Cover for Beds and Tree Rings

The choice being made on this page is usually mulch or stone. A bed on sandy west-side ground bakes dry by August and a bed on southeastern clay sits cold and wet until the thaw is well over, and both problems have a stone answer and an organic one. Shredded mulch is the organic answer, and it wins wherever the plants matter more than the surface does. It is shredded hardwood in consistent, medium-sized shreds, natural brown, laid two to four inches deep, and it does something no stone can: it breaks down and feeds the ground it is covering.

Brown shreds that knit together instead of floating off

Tip a yard out and it is a dark brown heap of fibrous shreds rather than chunks or nuggets. That shape is the practical difference. As the shreds settle over a bed they knit into one another and form a cover that holds together, so it is less likely to blow across the lawn in a March wind or float off down the drive in a heavy rain than a loose, chunky material would be.

Over the first season the color softens from fresh brown to a weathered gray-brown, which most people prefer around planting, and the surface keeps an even, finished look while it does so. Underneath, the layer is shading bare soil, slowing evaporation between waterings and cutting the light reaching weed seeds.

Beds, tree rings and the planting along a cold north wall

Flower borders and shrub beds are the main job. Two to four inches around ornamental planting holds moisture, keeps weeds down and buffers the root zone against the sharp swings at the soil surface that come with deep frost and repeated freeze and thaw here.

Tree rings are the second. A clean ring of mulch around a trunk keeps the mower and the string trimmer away from the bark, which is a more common cause of damage on a home lot than anything a winter does. Foundation plantings are the third, and the north wall of a house is where the buffering matters most, since that ground freezes hardest and thaws last.

One rule applies everywhere: pull the mulch back from direct contact with stems and trunks rather than heaping it against them, so the stems are not covered.

Shoreline edges, construction entrances and paver bases: three loads to place elsewhere

A pond or shoreline edge. Organic mulch floats. At the water's edge it lifts off in the first rise and ends up in the pond, and on a Great Lakes shoreline the combination of high water, storms and ice removes it entirely. Use River Rock for a decorative edge or RipRap where the bank is being worked on by waves and ice. Mulch belongs above the wet line, in the planting behind it.

A construction entrance. That is a job for angular stone that bites into soft ground and can be driven on, which is #4 Crushed Stone or 3/4 inch crushed stone. Mulch under a truck wheel turns to pulp immediately.

A paver patio base. A base has to compact and hold flat and never settle, and organic material does the opposite as it decomposes. That is compacted 21AA limestone with a setting bed of stone screenings on top.

Two to four inches, and when the deeper end is worth it

The published depth is two to four inches, and the range is a judgment rather than a formula. Two inches is enough on an established bed being topped up, around shallow-rooted plants, and anywhere you are trying not to raise the level against a house or a walk. Three to four inches is the choice on a new bed with bare ground between plants, on beds that dry out fast on sandy ground, and where weed pressure is high.

Two cautions. Deeper is not better past four inches, because a thick organic layer can stay sodden and keep air away from roots, and that matters more on clay that already drains slowly. And on any bed that has a slope to it, depth and hold are separate problems, so think about the edge before you think about the inches.

Yards for a 210 square foot bed and eight tree rings

Mulch is sold by the yard, so the arithmetic stops at volume more comfortably here than on any stone product.

Take a bed of 210 square feet at three inches.

• 3 inches is 0.25 feet, so 210 x 0.25 = 52.5 cubic feet
• 52.5 / 27 = 1.94 cubic yards, call it two yards

Now eight tree rings, each six feet across, with a one foot gap left clear around the trunk.

• Each full ring: 3.14 x 3 x 3 = 28.3 square feet
• The trunk gap: 3.14 x 0.5 x 0.5 = 0.8 square feet
• Mulched area per ring: 28.3 minus 0.8 = 27.5 square feet, and 27.5 x 8 = 220 square feet
• At three inches: 220 x 0.25 = 55 cubic feet, so 55 / 27 = 2.04 cubic yards

Together that is about four cubic yards. This site publishes roughly 600 lb per cubic yard for shredded mulch, about 0.30 tons per yard, so four yards is in the region of 2,400 lb. Mulch is light for its bulk, which is why a load that sounds small takes up half a driveway. Both layouts are illustrations rather than real gardens. The mulch calculator runs the same sums, handles circles directly, takes up to five areas at once and offers an extra five percent for the spread you lose along the edges.

What sits under the mulch, and what it cannot stand in for

Mulch is a cover, not a growing medium, and the three soil products here do different work. Screened top soil is the layer for a new lawn or a regrade. Garden soil is the compost-blended material a bed is actually planted into. Fill dirt is bulk earth for raising ground and has no business in a planted bed at all. Build the bed with soil, plant it, then cover it.

When you have a yardage, choose a quantity and a delivery date on this page. Delivery is arranged at checkout from your ZIP code, and mulch needs a firm, dry place to be tipped where you can get a wheelbarrow to it, since a pile left on wet grass for a week will kill the grass underneath it.