By Clayton Tschudy.
Summer is the time. Time to get out and get some gardening done. Time to stay active in the yard during COVID-19. Time to kill your invasive warm-season grass lawn and replace it with native alternatives that do the same job, with less water, and won’t take over your landscape with invasive runners.
Why is summer the time? Because to properly kill the overly rigorous warm-season turf grasses, especially Bermuda grass, you need to pull out the canister of RoundUp (or generic glyphosate)—hopefully from a dusty shelf in your shed where it has gotten pushed back behind your organic amendments and mechanical weeding tools that get much more use—and kill that grass during its active growing period, which is the warm season. Glyphosate is a systemic that will kill the roots. Now before you send me hate mail and tell me I’m poisoning the neighborhood, please know that I only ever use glyphosate when absolutely necessary. You can try removing your old lawn with plastic sheeting or lasagna layering of organic materials, but Bermuda grass is notorious for surviving all but the harshest removal techniques. So, if you have Bermuda go ahead and use the glyphosate, but with tactical precision so that you can use it just twice to kill nearly all the grass, and then put the rest of that canister away forever.
This targeted strategy is called Grow and Kill. Here’s how it works. Give your Bermuda lawn a good deep soak to activate as much of the root system as possible. A week later spray your lawn with a 2-5% solution glyphosate product making sure to wear gloves, a long sleeve shirt and pants, and a mask. Spray only when there is no wind. Wait two weeks and you will see most of the lawn go brown. Then give the lawn another deep soak. Wait a week or two for new green shoots to appear—this is the grass activating dormant roots to support new growth—and then spray once more. If you do this during the summer months when Bermuda is actively growing, you will successfully kill 95% of the Bermuda. The rest you can remove by hand over time.
The other reason to start this process now is that the native grass alternatives are cool-season grasses, plants that actively grow during our cool rainy season from November through May. If you have successfully killed your invasive warm season lawn during the summer, you will have an ideally timed installation window of October/November for your new, cool-season native lawn. And we have at least two excellent plant options for lawns that are actually native to San Diego County!
San Diego Bentgrass -
This beautiful, finely textured grass has recently become available as a roll-on sod product that can be installed just like traditional turf. It’s tough but delicate, an excellent substitution for fine fescues, but needs 50% less water for good results. This grass is summer dormant, but can be kept decent looking through the warm months with low, weekly water, and less mowing. A quick Internet search will find local vendors of San Diego Bentgrass sod.
Clustered Field Sedge -
If you need a lawn that is green year round, but can be a low-water substitute for the water-hungry tall fescue, try Clustered Field Sedge. As it is not a true grass, it never goes dormant. It has the texture of Kikuyu or St. Augustine grasses, but is not invasive. It can be mowed or left lumpy and combined with wildflowers to create a native meadow. This is a tried and true lawn substitute worth trying.
Clayton Tschudy, Executive Director of San Diego Canyonlands, is a botanist with over 20 years of experience in restorative landscape design in California. He began his career in environmental biology and is an expert in California native plant ecology. Mr. Tschudy was the Director of Horticulture at the Water Conservation Botanic Garden at Cuyamaca College for four years, and is recognized as an industry expert in habitat restoration and drought tolerant landscaping. He has consulted on many environmental projects with the City of San Diego, City of Chula Vista, local corporations, businesses, and private landowners. He can be reached by email -