Bermuda grass is one of the most feared perennial weeds around, even in the areas where it is considered a good lawn grass. It greens up easily in summer with good watering, but it goes dormant for the colder half of the year in our climate, so in this area it is a weed. It can travel up to 18 inches deep and easily travel under 6 feet of sidewalk to come up on the other side.
Bermuda grass, traveling over 4 x 8 sand.
But its large, strong rhizomes (traveling storage roots) are also its greatest weakness. They are fat and shiny, 1/8 to ¼ inch thick, easy to see and sort out from loosened soil. Their feeder roots are thin and wiry, with no food storage.
Dug Bermuda, showing its shiny rhizomes.
Like crabgrass, its annual, or considering it lives until frost, tender perennial, relative, they don’t re-grow from feeder roots. We know they are related because they have the same seed stalk, with four arms and small seeds. Crabgrass grows in a clump; Bermuda grows out of the ground. Cut a crabgrass crown off its roots and it is gone; get all of the shiny Bermuda grass rhizomes out of the soil and it also is gone. That is except for their seeds, which are small and easy to smother with mulch.
Bermuda grass with seed stalks
Mature crab grass; note the clumping growth and fat leaves.
While those rhizomes can travel deep, they don’t go any deeper than they need to travel, which is generally within a few inches of the surface.
They can be dug and sorted out of the soil. Push a shovel in the ground, and loosen the soil. Pull on the grass stems. Shake the soil off the roots, and put them in a bucket. Get all the rhizomes out of that shovel-full; move the shovel back a few inches; loosen the soil; pull the roots. Keep going until you get all of it.
It isn’t as easy as spraying Roundup (glyphosate salts). But killing those fat roots with glyphosate takes all summer, and you will still have to dig the stubborn bits that insist on growing back. They are too small to suck up enough glyphosate to kill the remainder, and those pieces may be resistant to glyphosate.
But after killing a lawn with glyphosate, you will have thereby fertilized the ground for broadleaf plants and annual grass, not perennial grass, and lawn grass won’t grow well. This is okay if you would rather weed a ground cover than mow.
Creeping Jenny, with 4 x 8 sand path
Creeping Jenny (Lysimachia) is a great soft green ground cover that doesn’t need mowing. It travels in a mass over ground, about a foot per month, at which point it starts to root. To stop its advance, keep pulling it as it moves into the area you don’t want it; it has soft stems that pull easily and don’t need cutting; it roots only about 2” deep. It is water dependent, and will warn one that it is getting dry by getting dull and flattening to the ground; the next step is to brown out. It can be brought back by watering, but not quickly.