Clearing the Space

It is typically necessary to clear existing vegetation to make space for new native plantings where a garden bed does not already exist. There are a few main ways to kill existing grass/weed vegetation: sheet mulching, solarization, sod stripping, and systemic broad-spectrum herbicide.

Each method has advantages and disadvantages, but we find that sheet mulching is the preferred approach for most residential landscapes. The size and shape of this planting is entirely up to you.

Sheet Mulching

For lawns or areas with tall weeds first cut down the vegetation as close to the ground as possible. A string trimmer works well for this. Lay out at least one layer of cardboard or several layers of newspaper, making sure to cover the entire area with no gaps. Top with several inches of mulch/compost to smother the unwanted vegetation. After about two weeks, you can clear away a portion of the mulch and cut a hole in the cardboard and into the ground to install live plants. The cardboard will generally decompose within one growing season. For more details, including a step-by-step video, check this out: How To Sheet Mulch

- If planting by seed it is recommended to leave the sheet mulch in place for a growing season to help achieve better clearing of the current grass/weed layer. Then remove the mulch and any non-decomposed paper/cardboard to reveal the soil beneath before sowing.

Solarization

This is most effective for sunny areas. For best results, use two layers of clear plastic pinned down across the space you wish to clear for 4 to 6 weeks. This uses the sun’s heat to cook the vegetation and will also kill seeds in the soil to a depth of 4-6 inches. A relatively inexpensive approach, it is highly effective on live plants as well as weed seeds and diseases A more detailed description of the solarization method is linked here.

Sod Cutting

This can be done using a shovel, or you might find a rental a sod kicker tool or a motorized sod cutter. The disadvantage with this approach is that it removes a valuable layer of top soil along with the sod roots. We recommend flipping the sod over "green side down" and leaving it in place. The grass will ideally be killed by drying out the roots and depriving the remainder of sunlight. The grass will decompose and enrich the soil.

Systemic Herbicides

This may not be a first choice but it might be a more practical option for clearing severe infestations of invasive plants. It is highly effective at killing all vegetation while leaving a very small residual risk of contaminating adjacent areas. The chemicals disintegrate into biologically inert components in a very short time period – generally within 3-5 days. Treated plants often show damage in a week or two. Occasionally, a few plants might have sufficient herbicide resistance to require a second application. Using a herbicide to kill existing vegetation will likely require 2-3 applications as new seeds germinate on the newly exposed soil.

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