Mowing my lawn is a chore that I do not usually mind doing. I get some exercise pushing my mower around the lawn, and I enjoy the time outside with just the hum of my mower and my own thoughts. And mowing produces the immediate and satisfying result of a nice-looking lawn. At least it looks nice for a few days, and then the KR Bluestem grassy weed sends up a tall seed head. Of course, the KR Bluestem is at the front of my yard where it just waves to all the neighbors.
KR Bluestem is a perennial grass that starts as a bunch-type grass and spreads by rhizomes and/or stolons. Texas is home to at least 27 species of bluestem grasses, and 21 of the species are native to Texas. You might have seen big bluestem, little bluestem, or broomsedge bluestem along the roadsides or in native prairie areas. Grasses like these are beautiful in the fall because their inflorescence, or flowering structure, really stands out. King Ranch Bluestem is one of the six non-native species in Texas.
KR Bluestem originated in China and was brought to California as early as 1917. It was introduced in Texas in 1924 at the Angleton Agricultural Research Service Station. The grass was first introduced to the King Ranch to be used in rangelands and pastures to provide forage for cattle and control erosion. During the years of the Dust Bowl in the 1930s, ranchers struggled to maintain pastures that were devastated by drought and overgrazing. KR Bluestem, along with the similar Kleberg Bluestem, were found to be drought tolerant and provided forage for cattle.
Seed was released for commercial production in 1949, and King Ranch and Kleberg Bluestem were seeded to decrease soil erosion along highways, spillways, and dams, and it was seeded in depleted rangelands across Texas and Oklahoma. KR Bluestem remained an important grass through terrible drought in the early 1950’s when farmers and ranchers were glad to have a grass that would hold onto the soil and provide some forage for cattle.
A grass that started as a problem solver in the 1930s and 1940s is now considered an invasive species. King Ranch Bluestem is notorious for invading an area and dominating all other vegetation. Native grasses and plants cannot compete with the thick stands of grass, creating a monoculture that drives out plant and insect biodiversity.
KR Bluestem can be tough to remove from a lawn, and it tends to spread in lawns that have thin turfgrass or poor nutrition. Herbicides that are effective at killing grassy weeds will also kill desirable turfgrass. You can carefully spray herbicide on the KR Bluestem, but you’ll be left with a dead circle of grass in your lawn. Mowing encourages KR Bluestem to spread out horizontally, so that is not an effective control method either.
The most effective method I have found in my own lawn is to spot treat it with glyphosate and dig it out. The recent rains helped make it easier to dig out this thick weed, and I am often seen wandering around my front yard with a handful of KR Bluestem.
For more information about lawn and garden topics, contact Kate Whitney at the Williamson County AgriLife Extension Office at 512-943-3300.
