Drive alongside any roadway in Northeastern Oklahoma and you’ll possible see giant swaths of Johnsongrass (Sorghum halepense) overlaying the shoulders and ditches.
Johnsongrass is a warm-season grass that types large colonies and may take over areas in a single season. One medium-sized clump can create as much as 60 ft of rhizomes in a single 12 months. From these rhizomes, giant, finger-sized stems will emerge that may tower over 6 ft tall and are topped with a panicle of flowers that produce a purple/purple seed head, able to producing two kilos of seed. It appears like a dream come true for a rancher and a nightmare for a row-cropping farmer or house gardener. Because it seems, Johnsongrass is usually only a nightmare for everybody.
The fable of how Johnsongrass grew to become one of many nation’s prime 10 most noxious weeds dates to the early nineteenth century, when an imported grass from the Mediterranean had taken over the plantation of South Carolina Gov. John Means. Later, Alabama planter Col. William Johnson acquired a few of Gov. Means’ seeds and took them to his plantation close to Selma. He started to freely share seeds with different Southern aristocrats, and thus, “Johnson’s grass” was born.
Immediately, Johnsongrass plagues the fields of farmers and residential gardeners, whereas concurrently worrying ranchers due to its tendency to retailer nitrates and produce cyanide at any time when harassed, each of which may kill livestock. Johnsongrass now runs amok all through the southern U.S. and we largely tolerate it. Nevertheless, when it frequently pops up in your backyard mattress, you in all probability surprise, “What can I do to do away with this?” when you need to be asking. “How a lot do I’ve to do to do away with this?” The reply is “rather a lot.”
Managing undesirable Johnsongrass shall be extraordinarily troublesome and intensive. A sound, built-in technique should be used to forestall new seed import, deplete the present seed financial institution, and deplete the vitality shops of current rhizomes. It’s endorsed that you just make use of mechanical, organic, and chemical pest administration to be efficient.
Forestall new seed import by being knowledgeable about your animals. Livestock which will have consumed Johnsongrass ought to stay idle for not less than every week to keep away from spreading seed by means of excretion.
Deplete the present seed financial institution and the vitality shops of current rhizomes by manually eradicating younger shoots, however ensure to take action when the bottom is softened to take away a great portion of the rhizome. Scalp (mow) the world repeatedly to lower the photosynthetic functionality of the grass, which can weaken the plant’s rhizomes. Grazing can lower the shoot rely – equally to mowing – however care should be taken to not permit the animals to eat harassed Johnsongrass, as it may be deadly. You should use soil solarization plastics to cowl giant areas for a season to break the rhizomes vitality shops. Chances are you’ll elect to make use of tillage as a method of administration. Tilling could be efficient when utilized in an built-in program, however tilling alone will possible do extra hurt than good by fragmenting the rhizomes and multiply the problem.
Chemical strategies needs to be used appropriately to achieve efficient management. Use a systemic post-emergent herbicide on the correct time for one of the best management. Grass-selective herbicides (fluazifop, clethodim, or sethoxydim) needs to be utilized when vegetation are 8 to 18 inches tall and nonselective herbicides (glyphosate) needs to be utilized when vegetation are 12 to 24 inches tall. In both case, probably the most harm could be inflicted on the rhizomes when the vegetation are flowering, however not seeding, as a result of the rhizomes are rising vigorously at that time. Grass-selective herbicides will harm candy corn.
Correctly use all the pieces at your disposal to start to battle Johnson’s grass and name the Cherokee County OSU Extension Workplace for help.
Garrett Ford is an agriculture educator for the Oklahoma Cooperative Extension Service in Cherokee County.