Yesterday, I was asked to identify a grass that was invading a grass hayfield near West Lafayette. The 12-inch tall specimen was in a plastic sandwich bag. The old growth of 2020 was beige-bronze in color, narrow leaved, and had tufts of pubescence remaining. Most seed had been windblown during the fall and winter. My “hunch” as I approached the sample on the table was broomsedge bluestem (Andropogan virginicus). The warm-season perennial bunchgrass was just breaking winter dormancy and had very flat and narrow leaf sheaths. I reached for my cell phone and used a plant identification app. Whoever programmed the app thought the plant was broomsedge bluestem, too!
Broomsedge bluestem invasion is occurring in a grass hayfield. (Photo Credit: Keith Johnson)
One of my first Purdue Extension in-field education events in the early 1980’s was my introduction to broomsedge bluestem. Areas of the southern Indiana grass pasture had more broomsedge bluestem than the desired forages that were seeded. I recall that a farmer leaned over and said “We call it poverty weed”. I once thought that broomsedge bluestem was a southern Indiana plant only, but as the years have gone by I see the plant all over Indiana. A few years ago, a group of farmers were doing sensory analyses of different hay samples and chemical analyses were available, too. One of the samples on display, was broomsedge bluestem. The chemical forage analysis verified why the grass has the nickname poverty weed. It would have made better bedding than a feed resource.
Broomsedge bluestem is a biological indicator plant. Where it becomes invasive it is common that the soil pH and/or phosphorus level are very low. The method of reducing broomsedge bluestem is to not investment in an herbicide application, but to apply the recommended amount of limestone or fertilizer as determined by a soil test. Slow but sure, the desired forages will become more dominant.
As hay is harvested, nutrients are being removed. In time, deficiencies will occur if nutrients are not wisely replaced by commercial fertilizer or livestock manure applications. Don’t let your field go into poverty status!
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