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Over the Garden Fence

Landscape Mulch with Expectations

By this time of the year, there has already been a lot of landscape mulch applied for the summer. Landscape mulch can provide more benefit than just how nice a freshly applied layer looks.

When applied around young trees, we know that it reduces the competition from grass and makes it easier for the tree to establish in the new location. The tree gets more water and has no competition for soil nutrients. A big plus is there is no need to trim grass away from the trunk saving the tree from the destructive string trimmer!

When mulch is applied at the recommended depth of two to three inches, once settled, the tree or plant also benefits from water conservation. Having mulched beds can make the difference of a plant being stressed or not. Stressed plants are more likely to attract insects and are more disease prone.

Another benefit is weed management. Those weed seeds are around, yet kept in the dark, so they remain dormant. For the few annual weed seedlings that do make it to the surface, they can be pulled easily. Getting the bed clean is always helpful. Get rid of existing weeds and leave the soil surface loose to more readily absorb water. There are those perennial weeds that will re-sprout, so be on the look out and get them out as soon as you see them by cutting them below the mulch layer or spot treating with a non-selective systemic weed control product. Be careful not to damage surrounding ornamental plants.

Our grasses typically grow towards our landscape beds, from two to four inches a year. Before you mulch, consider edging that bed. This is always a good time to consider any bed line changes as well. Consider the turning radius of the riding mower or the fact that perennials and shrubs are growing out farther than the existing bed line. The bed will look much better and more "relaxed." Another bonus of bed expansion is less grass to mow and the ease of mowing with the new bed line.

Nothing comes without problems and landscape mulch is no different. Organic mulch will immediately begin to decompose once applied and with that come some familiar and unfamiliar bits of nature. We easily recognize mushrooms, and understand they come from weather conditions where periods of rain and cool temperatures promote them. You can see mushrooms protruding up and out of the mulch.

Extension Master Gardeners often get calls of other "things" found on the surface of landscape mulches. Slime molds can appear in several colors and show up in hours or overnight. They have some common names being very descriptive of what they look like! Mushrooms and slime molds appear with the right conditions in the mulch and can be avoided or stopped when they do show up by loosening the mulch with a tined digger or landscape rack to dry out the mulch. Doing nothing is always an option, as those mushrooms and slime molds will only be there a few days.

About the author: Richard Hentschel’s expertise extends across several subject areas with specialties in lawn care, fruit tree production, woody ornamentals, and home and community gardening. During his 45-year career in horticulture and agriculture, Hentschel became a well-known and respected expert for commercial and homeowner audiences, industry organizations, and media. He retired from University of Illinois Extension in April 2022 with nearly 30 years of service as a Horticulture Specialist and Educator in northern Illinois.