Q: I would like to convert a corner of my irrigated bluegrass yard into a drip-irrigated, mulched area for growing xeric perennial flowers. What is the best way to remove the grass?

A: Digging out the grass and replacing it with a layer of top soil can be worth the effort if your soil is heavy clay—a common problem in the Front Range. An easier option for eliminating turf is to spray the actively-growing grass with glyphosate (Roundup® is possibility). After a week, the treated grass will turn brown and a layer of mulch (or fabric and mulch) can be applied. It is important to avoid spraying turf or plants you would like to keep, so consider shielding plants close to the spraying area with cardboard or plastic. Installing a brick, metal, rock or timber edging around a new mulched area before spraying also can help focus the chemical spray.

The U.S. Environmental Protection Agency advises that “glyphosate is strongly adsorbed to soil …and microbes in the soil readily and completely degrade it even under low temperature conditions;” but if you still prefer to forego chemical use, it is possible to simply smother out the grass. To do this, overlap black and white newspapers on the grass, using about 10 sheets of newsprint for enough thickness to restrict light. Then cover the papers with two inches of shredded mulch or 3-4 inches of chip type mulch. The paper and mulch will smother the grass, and gradually the newspapers will disintegrate into the soil. For further information see Fact Sheets # 7.234 “Xeriscaping: Retrofit Your Yard” and #7.760 “Mulching with Wood/Bark Chips, Grass Clippings and Rock.”

Q: Should I place weed-barrier fabric under new mulch or gravel?

A: A fabric will help restrain weeds or grass, especially in gravel, cobbles, around stepping stones or along the edges of mulched areas. Use a porous fabric with a textured or rough surface, since mulch clings better to rougher fabric. Do not use slick, impermeable plastic sheeting, since this will restrict the air and water passage that is essential for plant growth. Some gardeners prefer to use no fabric under the mulch in a flower and perennial shrub area—or perhaps to use it only along the edges of the area. Not using fabric in a garden bed allows for flexibility in moving or adding plants and allows ground cover plants to spread.

Q: I live in a windy area. What mulch is least likely to be blown away?

A: The choice of mulch color, style or composition is largely a matter of personal preference; however, if blowing wind or slopes are a concern, then consider a finely shredded redwood or cedar bark mulch. These mulches cling to themselves or to weed fabric and are less likely to blow away or slide.

Gardening and Insect Fact Sheets are available on-line by clicking HERE.

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This page updated:  July 3, 2006