Controlling King Ranch Bluestem Weeds
By Office of Communication
Posted on November 27, 2012, November 27, 2012

Have you noticed the lanky grass on the medians above the grass line? Have you ever thought to yourself, "Why won't the city cut our grass more often?' The answer isn't that simple. What you've noticed is the King Ranch Bluestem weed - a weed the entire state has been at war with for years.

When King Ranch (or KR) Bluestem (Bothriochloa ischaemum var. songarica) was introduced from Europe and Asia in the 1920s and 1930s, it was seen as a desirable species for erosion control. The plant, by its nature, is drought resistant and quickly establishes itself by growing an average of one foot per week. It may have been too effective as it is now considered invasive and its presence threatens the abundance and diversity of native species. Scott Crossnoe, Park Services Supervisor, describes the weed as awful and impossible for the city to control from a financial perspective.

"The Texas Department of Transportation started using KR Bluestem for wildflower sustainment, and roadside vegetation, and it has since gone broad across the state,' said Crossnoe. "It busts out in the fall, usually from September through November, and takes over everything. There's really no effective way for us to fight it.'

Crossnoe said that the City of Arlington stays on a bi-weekly mowing schedule for medians and right-of-ways, with the exception of a few 3-week periods during the summer when the grass doesn't grow as quickly because of the heat. The introduction of a weekly mowing schedule during the fall months to combat the bluestem would be extremely expensive.

"In order to combat this invasive species we would have to go on weekly mowing schedules - and even that wouldn't fully control it,' said Crossnoe. "The cost to mow medians and right-of-ways in Arlington is about $40,000, per cycle. An additional 4-6 mowing cycles would cost an estimated $200,000 a year.'

Chemical applications have also been found to be ineffective against KR Bluestem. Many cities across Texas have tried chemicals such as of MSMA (Monosodium Methyl Arsenate), with minimal success. The damage to the natural environment has helped rule out chemical applications as a defense against the KR Bluegrass.

For the time being, it looks like there is no effective answer to combat the KR Bluestem that is dominating the state of Texas. The only sure-fire way to end the Bluestem infestation is cold weather; therefore, until we get a good frost or two, we won't see the end of it.

Controlling King Ranch

King Ranch Bluestem weed on median

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