KC Gardens

Mulch is good for the garden. Here’s how it can go wrong, and how to do it right

Christmas trees become mulch for Happy Trails program

Your donated Christmas tree, minus all decorations, can become mulch for local trails through the Happy Trails program.
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Your donated Christmas tree, minus all decorations, can become mulch for local trails through the Happy Trails program.

It seems like just about everyone is doing it — mulching.

Mulching is an important gardening practice that offers several benefits. The most important is the ability to conserve moisture and keep the soil cooler during a long, hot summer.

Mulch is beneficial for stopping unwanted weeds around trees, shrubs and flower beds. A freshly mulched area is the finishing touch, like frosting on a cake.

Mulching takes little brainpower, just persistence and a strong back. However, there are a few common mistakes to avoid.


One common mistake when mulching around trees is applying too close to the trunk. Prolonged exposure of the trunk to the moist mulch results in decay of the bark layer, leading to poor growth or death.

When properly applied, mulch should start a few inches away from the trunk and extend at least 3 feet out from the base. The depth of the mulch layer should be about 3 inches and no more than 4 inches.

When mulching trees, keep in mind the mulch pile should look like a doughnut, not a volcano.


Follow the same depth guidelines for trees when mulching shrubs. Caution should be used when piling mulch around the base, or trunk, of the plant. Place the mulch a few inches away from the base.

Shrubs look best in the landscape when large beds or groupings of plants are all mulched together. Remove any grass between the shrubs or other plants and mulch the grouping as a whole.

Flowers and vegetables

A 3-inch layer is recommended. Use finer textured materials for vegetables and flowers than those used for trees or bushes.

Vegetable gardens are best mulched with materials such as straw, leaves or grass clippings that break down by the end of the season. Avoid working wood chips into garden soil as it can slow growth as it decomposes.

Mulch color

The kind of mulch you use is a personal preference. All mulching materials that are organic, except rocks, provide the same basic function. The difference is in the texture, color, lasting power and, of course, cost.

Trees and shrubs look good mulched with just about any material. Flower gardens look best against a darker color and finer grade of mulch.

The plants should be in the spotlight and the mulch just a covering. Some people use red-colored mulch, which in most cases makes the mulch the glaring focus, not the plants. Consider the desired effect in the garden before purchasing mulch that is not a soft, earth tone. In other words, mulch is not meant to be seen.

No matter which product is chosen, it is important to follow a few guidelines, not only for a beautiful landscape but for healthy plants. Plants that are well adapted will require less water, grow vigorously and need fewer pesticides and fertilizers.

Dennis Patton is a horticulture agent with Kansas State University Research and Extension. Got a question for him or other university extension experts? You can also email them to garden.help@jocogov.org.

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