It’s spring, and the homeowner’s thoughts turn to mulch. Nothing like a new layer of mulch and a freshly cut bed edge to make a yard look sharp. But more than good looks, mulch provides functions in two ways:

  1. Mulch helps the soil retain moisture and helps channel more rainfall into the soil.
  2. The right mulch will inhibit weed growth. It will not eliminate weeds, but it gives the gardener the upper hand.

Before spreading mulch this year, consider the following guidelines:

Mulch volcano

Don’t Mound Your Mulch: Not only do “mulch volcanoes” make your trees look a bit silly, they increase the risk of pests and disease. When mulch is mounded up around a tree trunk, it creates a warm humid environment — ideal for a host of insects and diseases problems.

When spreading mulch, apply it evenly around the base of the tree. It should be flat — not mounded up — and pulled back a few inches from the trunk.

Mulch thickness

Don’t Spread it Too Thick: If the layer of mulch is too thick, it will absorb rainwater and prevent it from reaching the root zone. In areas where fresh mulch is applied every year, an impenetrable shell can form, causing all water to run off.

The proper thickness depends on the mulch you use. In most cases, 3-4″ is fine. Some mulches, such as buckwheat hulls, will break down over the winter and can be turned into the soil. Other types of mulch, such as shredded bark, do not break down sufficiently. Before applying a fresh layer in the spring, remove some or all of the mulch from the previous year and add it to your compost pile.

Mulching Tip from a Reader

“Having moved into a new home and bare landscape last year, among the items on the ‘to-do’ list was our landscaping, which required much mulch, so we ordered a full dump truck of dark mulch. It was dumped in four large piles that almost took your breath away when you thought about how to move it all over the lot.

“The only items at hand were a couple of plastic sleds. We would ease the side of the sled up to the mound and pull the mulch into the sled and the grandchildren ran to each area to spread the mulch – a regular production line!”
—John & Ann Barton, Soddy Daisy, TN

Choose the Right Texture: Coarsely textured mulch (with individual pieces that are 1″ or more in diameter) will not pack as tightly as finely textured mulch. Because wind-blown seeds — and light — can get between the larger pieces, coarsely textured mulch tends to be less effective at suppressing weeds. Small plants can also look dwarfed when they’re surrounded by big chunks of bark or 2″ pieces of stone.

Mulching materials vary by region (bark chips and shredded bark mulch in the Northeast, pine needle and stone mulch in the South, compost and straw in the West). Use whatever mulch is most available in your area, but also consider matching the texture of the mulch to the size and type of plants you are mulching around. Remember that brightly colored mulch will draw more attention to itself. A mulch that looks more like soil will keep the focus on your plants.

—David Grist, Gardener’s Supply
David uses finely ground spruce-fir bark mulch.