Tips for battling Bermuda grass
BERMUDA GRASS IS THE BANE OF A GARDENER’S EXISTENCE. It is a warm season grass, and in our climate, actively grows during the mid-spring and summer season. It is dormant in winter and looks dead. Don’t be fooled. Creeping through the soil, or along the surface, thick distinctive yellow roots or above-ground shoots called rhizomes crawl and spread in every direction.
Bermuda grass can grow a couple of feet a year. It is often found in lawns, and from there — if not controlled — spreads into flower beds where it threads its way through other plant’s roots, effectively making the grass impossible to remove without digging up and removing plants it has become intertwined with.
Bermuda grass propagates both vegetatively from rhizomes and also from seed, but the rhizomes are by far the fastest and most effective way it reproduces. If soil is rototilled, each tiny piece can root and grow. If you dig it out, each piece left behind will grow. There are, however, various ways to control and remove Bermuda grass. Some require time and patience, others painstaking digging and weeding. Some opt for spraying it with herbicides. You can minimize its presence in your lawns by using specific lawn care practices.
Bermuda grass is an introduced grass probably originating from tropical Africa, not from Bermuda. It very likely came in as seeds in contaminated hay, and there are also records of imported Bermuda grass seed in Georgia in the 1700s. Reports of flats of Bermuda grass being sold in San Francisco in 1856 for $5 exist. It has since spread to many states as a weedy plant in gardens and on farms. Worldwide, it is considered one of the most problematic weeds for farm crops in the grass family. Improved hybrid strains of Bermuda grass are used as a turf grass in the southwest. Other strains are used as pasture grasses.
If you have a patch of Bermuda grass in your garden, the time to act is now. Dig it all out before it spreads and becomes a much bigger, more complex problem. If soil is moist, this task is fairly easy although tedious. After you are finished, repeatedly check the area during the growing season. Diligence is necessary to continue to dig out and remove any stray strands that survive your removal efforts. Do this right away before these strands gain strength.
BERMUDA GRASS IN LAWNS: In our area it thrives in dry infertile soil. In a lawn, it is usually found where lawn grass is weakest due to poor growing conditions such as too-low mowing, inadequate irrigation and poor soil fertility. Many lawns contain all of these conditions. Robust lawn grasses (especially fescues) adequately watered, fertilized and mowed at the highest lawnmower setting can usually out-compete Bermuda grass. If you have Bermuda grass in your lawn, water regularly, fertilize in the appropriate seasons, and very importantly, mow at the highest settings. Bermuda grass should diminish over the course of a season or two. In the fall, seed any weak areas with grass and clover seed. Strawberry clover is an excellent, drought-resistant lawn clover.
SPRAYING BERMUDA GRASS FOR REMOVAL: Some people are adamantly against spraying herbicides, while others will resort to spraying herbicide to kill Bermuda grass. This column does not recommend this practice in particular - but contains information to minimize the use of herbicide products if you make this choice. Some people say that herbicides don’t kill Bermuda grass, but sprays are effective using specific methods. Spraying Bermuda grass when dormant won’t kill it so don’t spray in winter, early spring or late summer. Wait until the grass is green and actively growing in early or mid-summer, then spray. One application should kill almost all of it. A very small amount of spot re-spraying or digging should take care of any areas that did not get adequate coverage the first time. The Bermuda grass at this point can be safely dug out, removed with a sod cutter, or can be sheet mulched over. “Organic” spray products such as vinegar will only burn the surface growth back and will not affect the vigor of the underground growth parts.