Weed Control - Quackgrass & Bermuda Grass
& Bermuda Grass
respond much the same way to cultural and chemical control methods. These are both very hardy perennial grasses that require plenty of chemical and correct timing to have any success at control. Bio control measures for these two grasses are non-existent. Even drought only places them in a form of suspended growth from which they readily begin a period of rapid growth at the first sign of irrigation. Once again, it is extremely important that you READ AND FOLLOW THE LABEL with any herbicide you chose to use. The "time line" featured near the bottom of the page represents a generalized guide to the most effective timing of chemical weed control here in Northern Utah.
"One of the more common questions I'm asked is how to control bermuda grass in the lawn. My standard reply is 'asphalt'," says Jerry Goodspeed, Utah State University Extension horticulturist. Unfortunately, bermuda grass can grow through asphalt and really thrive. It is a constant problem out on our county roads. Timing is everything in applying chemical on bermuda grass, especially in non-crop arenas. Dual action herbicides (both folar and root uptake) are very effective but can be costly.
For Bare Ground, we like Arsenal® or Oust® tank mixed with diuron applied when sufficient moisture is available for incorporation for most all bare ground jobs. This would generally mean early spring or late fall. Either one of the first two chemicals mentioned used alone will do the job on bermuda grass and quackgrass, but will leave little or no protection behind for resistant weeds such as kochia. Timing gets to be a problem when trying to take advantage of the dual action properties of Arsenal® or Oust®. The best time to kill perennial grasses through folar action is when they are mature and flowering. Very little rainfall is available at that time of year to incorporate the herbicide into the ground for root uptake. So, if all you are going to get is folar action anyway, perhaps Roundup® is the most cost effective choice. See labels for rates on your soils. CAUTION Watch sloping ground for potential runoff in the event of heavy rain or overhead irrigation!
Roundup® may be the best bet on quackgrass and bermuda grass, particularly if the infestation is solid and a few years old. A 3 quart rate is effective and a good surfactant is a must! Because the best timing for good action on these grasses is well into the growing season (July or August) an application of 2,4-D earlier on to control young broadleaf weeds among the grasses not yet mature enough for a Roundup® application can be a good thing. Mowing is not acceptable as the stand of unlawful grass will not be set back at all and the very fine seeds are easily spread via the implement to other non-infested areas.
Rights of Way
Quackgrass and Bermuda Grass next to irrigation ditches and streams must be treated with care. Arsenal® is widely used along concrete irrigation ditches to control these damaging perennials but overspray into the irrigation stream must be avoided. Roundup® or Rodeo® are also very good in these situations and chemical allowed in the water is of little downstream consequence. You put a pencil to the rates and use the one that is cost effective for your budget.
Along Roadsides, these weeds are a terrible problem for two reasons. First, in many parts of the county, deep drain ditches run along side the roadways and it is the bermuda grass that holds the side of the ditch against soil erosion and resulting road shoulder damage which would turn into a safety hazard. In these instances, we allow bermuda grass to thrive. It is a dilemma from which there is no viable escape. Secondly, these powerful grasses can and do thrive in the asphalt edges of the road and given enough time will destroy 2 feet or more of asphalt. There never seems to be enough exposed leaf area to get a good kill with herbicides and any kind of incorporation for protection offered by residual chemicals after the asphalt is put down is not going to happen. We do our best in these problem areas with 3 quarts of Roundup® and a surfactant. Prior to asphalt re-surfacing, we shave off the bermuda grass with a motor grader and apply Arsenal® and diuron to the edges of the right of way.
Alfalfa is a crop that can have a problem with both bermuda grass and quackgrass. There are a few selective herbicides labeled for these two perennials. Poast® (sethoxydim) will provide good control on bermuda grass and partial control on quackgrass. Kerb® (pronamide) is still a great choice for control of quackgrass in established alfalfa. Others such as Velpar® and Karmex® will yield partial control. These herbicides should be applied when alfalfa is dormant but not when ground is frozen. The best defense continues to be a clean seedbed from the start and a dense, healthy stand of alfalfa.
Corn is also plagued by these perennial grasses. There are herbicides that include bermuda grass and quackgrass among the weeds controlled on their label. Perhaps the most effective way to rid corn ground of bermuda grass is to allow it to green up after the corn is chopped and apply 3 quarts of Roundup®. This should be followed in 2 weeks with deep tillage.
Most appropriate months for treatment of quackgrass & bermuda grass
March and November being the best for bare ground applications.