Broomsedge grass is neither a true Brome or sedge

Published 12:00 am Monday, November 7, 2011

As you’re driving through the countryside, have you ever wondered what that dead-looking, brown, fuzzy, stemmy weed was that was covering a pasture?
Broomsedge (Andropogon virginicus), also known as Brome Sedge, is a very common, very easily identifiable, perennial bunch grass found in pastures, hay fields, roadsides, and anywhere else it can find to grow. Ironically, Broomsedge is not a member of the Brome Family of grasses, nor is it a true sedge. It’s actually a member of the Bluestem Family of warm season grasses.
Broomsedge is native to the Southeast and earned its name from the once common practice of gathering mature plants, tying them into a bundle, and then using the bundle as a broom.
Broomsedge is a very undesirable grass species in pastures and hay fields, as it has very little nutritional value, especially when mature. A heavy infestation of broomsedge is often considered to be an indicator of a pasture or hay field with poor soil fertility, low soil pH, and/or has been subjected to poor management.
According to information from Auburn University, low soil pH and/or low soil fertility often play a role in allowing broomsedge to become established, but correcting these conditions may not immediately eliminate a population of broomsedge plants. Broomsedge is actually not very competitive, especially the seedlings. It is difficult for young broomsedge plants to become established when soil fertility and pH levels are relatively high and there are well-adapted, vigorous forage plants covering most of the surface area of a pasture or hay field. Once broomsedge becomes established, its ability to compete greatly increases.
Defoliation (grazing management, clipping, etc.) strongly influences the ability of broomsedge to become established and survive. Broomsedge becomes extremely unpalatable as the forage becomes more mature. This characteristic of broomsedge allows it to become established most easily in situations where pastures are undergrazed in the spring and early summer, but overgrazed in mid- to late summer. If pastures are undergrazed in the spring, young broomsedge plants (which would be weakened by grazing if the stocking rate was higher) are allowed to reach the stage of maturity at which they become very unpalatable.
In summer, hot weather and/or drought often slows pasture growth, especially of cool season grasses like Tall Fescue, and livestock will eat the accumulated forage growth. However, at this point, livestock will heavily graze the improved forage species, but refuse the broomsedge. Thus, reducing the competitive advantage the improved forage species otherwise have.
Control is broomsedge is best described as, it’s easier to keep broomsedge out of a pasture than it is to get it out. Elimination of this pest can be easily accomplished over time with persistent application of proper management.
Using well-adapted, vigorous forage species and varieties, in addition to regularly testing the soil, followed by applying the recommended fertilizer and lime, will generally keep broomsedge out of unwanted areas.
Adjusting the stocking rate or by clipping pastures periodically will help the “spring undergrazing-summer overgrazing” situation described earlier.
Eliminating low soil fertility levels, low soil pH, and/or the defoliation schedule will eventually eliminate the broomsedge. However, this takes time because broomsedge is much more competitive once it has a good root system established. In some instances, liming and fertilizing a pasture or hay field very well for several years will reduce the broomsedge population, but it’s a slow process.
In cases where a thick stand of broomsedge predominates a low population of desirable forage species, it may be best to renovate the pasture or hay field. This generally requires killing the existing forage species either with tillage or non-selective herbicides, then reseeding or resprigging desirable forage species.
The ideal time to sow cool season grasses is the end of August-October 1, while seeding warm season grasses is best done from May 15-June 1. Keep in mind that Mother Nature may significantly widen or close that window of time.
Brad Johnson is an extension agent with the Rowan County Cooperative Extension. Contact him at 704-216-8970