Broomsedge ( Andropogon virginicus ) is one of the
most frequently-encountered noncultivated plants in
Alabama . Despite the taxonomic implications of its
common name, this plant is a grass , rather than a
sedge . It is widely adapted and commonly present in
non-cropland areas and pastures throughout the Southeast.
Broomsedge is native to our region, and its name arose
from the once-common practice of collecting mature
plants, tying them into a bundle, and then using the
bundle as a broom. Because this species is so widespread
and visible in the Southeast, it is easily recognized
and widely known to a high percentage of people, including
many urban dwellers.
Although it is no longer used to make brooms, broomsedge
still serves some useful purposes. It helps reduce
erosion in abandoned fields and waste places, it helps
provide cover for wildlife, and the golden color of
mature broomsedge brightens many areas, which would
otherwise be drab.
Unfortunately, broomsedge is an undesirable species
in pastures. It has relatively little nutritional value
for livestock, but it takes nutrients, water, sunlight,
and space that could otherwise be used by more desirable
plants to produce good quality forage. A heavy infestation
of broomsedge is often considered to be an indicator
of a poor pasture.
Reasons for Broomsedge Encroachment
It is commonly believed that any area infested with
broom-sedge is low in fertility or has a low soil pH.
While this often is the case, it is not necessarily
so. Low soil pH and/or low soil fertility often play
an important role in allowing broomsedge to become
established , but correcting these conditions may not
immediately eliminate a population of broomsedge plants.
In addition, the extent of defoliation greatly impacts
on broomsedge establishment and persistence as will
be explained later.
Broomsedge is actually not highly competitive, and
this is especially true for seedlings. When soil fertility
and pH levels are relatively high and there are well-adapted,
vigorous forage plants covering most of the surface
area in a pasture, it is difficult for young broomsedge
plants to become established. Once they do become well-established,
their ability to compete greatly increases.
It is possible for broomsedge
to invade a pasture even when soil pH and fertility
are near optimum. An example of this is when a forage
species is planted that is not well-adapted to the
site, resulting in a weak stand of forage plants.
Broomsedge might be considered an opportunistic" plant;
it doesn't force its way into pastures, it merely
takes advantage of opportunities!
As mentioned earlier, defoliation (especially grazing
management) profoundly influences the ability of broomsedge
to become established and survive. Broomsedge becomes
extremely unpalatable as the forage becomes more mature.
Therefore, though livestock will consume the young
growth, they will refuse it under almost any circumstance
once it becomes 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
growth at which they become highly unpalatable.
In summer, drought and/or hot weather often slows
pasture growth (this is particularly true with cool
season perennial grasses such as tall fescue) and livestock
begin to consume the accumulated forage growth. However,
at this point livestock refuse the broomsedge and heavily
graze the improved forage species. This has the effect
of reducing or eliminating the competitive advantage
that improved forage species otherwise have .
In controlling broomsedge ,
the old adage, "an ounce
of prevention is worth a pound of cure" applies. It
is easier to keep broomsedge out of a pasture than
it is to get it out, but elimination of this weedy
pest can be accomplished easily enough over time with
persistent application of the right management.
The selection and use of well-adapted, vigorous forage
species and varieties are certainly helpful in keeping
broomsedge from becoming established. In addition,
soil testing on a regular basis followed by the application
of recommended fertilizer and lime will, in most cases,
keep broomsedge out.
The "spring undergrazing -summer overgrazing" situation
described in earlier paragraphs should be avoided.
This can be done either by adjusting stocking rates
as necessary or by clipping pastures periodically.
To the extent that pastures are grazed or clipped without
exceeding the tolerance limits of the particular forages
being grown, the more difficult it is for broomsedge
plants to be competitive.
Broomsedge is a perennial, which
means that established plants will normally "come back from the roots" year
after year. This is especially true if the low soil
fertility levels, low soil pH, and/or the defoliation
schedule which allowed them to become established continue.
Eliminating these conditions will eventually eliminate
the broomsedge , but it takes time to do so because
broomsedge is more competitive once it has a good root
In some instances, doing nothing other than liming
and fertilizing a pasture well for several years will
reduce a broom-sedge population, but this may be slow
process. This will usually stop the spread of this
weedy grass, but it may take a long time to significantly
reduce the broomsedge population.
In cases in which there is a thick stand of broomsedge
and only a low population of desirable forage plants,
it may be desirable to renovate a pasture. This would
normally require killing the existing broomsedge either
with non-selective herbicides or with tillage, then
reseeding or resprigging desirable forage species in
If this is accompanied by fertilization and liming
according to soil test recommendations and by frequent
defoliation, any broomsedge plants which escape the
tillage and herbicides or which come from seed present
in the soil will be at a great competitive disadvantage.
At present there are no labeled herbicides that will
selectively remove broomsedge without harming desirable
An old University of Tennessee
Agricultural Experiment Station circular titled, "Control of Broom Sedge" long
ago revealed that management can eliminate broomsedge
. This publication, written by L.R. Neel and published
in 1936, reported the results of several experiments.
These studies dated back as far as 1927 and were aimed
at learning more about broomsedge and how to control
The tests discussed were conducted at the Middle Tennessee
Experiment Station and were designed to evaluate the
effects, which the following treatments would have
on broomsedge stands:
(1) application of commercial nitrogen fertilizer
or livestock manure; (2) defoliation; and (3) competing
forage crops. Because the soils at this location were
known to contain good levels of phosphorus and potassium,
application of these nutrient elements was not included
as experimental treatments.
Results were dramatic. Application of 200 pounds/acre
of nitrate of soda or 150 pounds/acre of ammonium sulfate,
together with grazing and two or three clippings per
year reduced broomsedge stands from 90% ground cover
to less than 5% in four years. These same treatments
resulted in good forage stands in areas where forage
crops had been seeded.
In a companion test, the lifespan of broomsedge was
evaluated by space planting broomsedge plants with
no treatments imposed except that half of the plants
were clipped regularly.
The result was that half of the plants had died out
by the end of 3 years, nine-tenths were gone by the
end of 6 years, and all had died by the end of the
7th year. The rate of death was more rapid where regular
defoliation had occurred. This implies that in areas
where broomsedge persists over a long period of time,
reseeding as well as perenniation is occurring.
The experimental results were corroborated by observations
of the effects of grazing and fertilization on some
400 acres of permanent pasture on the Middle Tennessee
Experiment Station. It was noted that pastures which
were kept grazed closely in spring and early summer
for several straight years had very little broomsedge
remaining, while in other pastures where lax grazing
had occurred, populations increased despite good fertilization.
The key to controlling broomsedge is to ensure that
desirable forage plants have a competitive advantage.
This includes maintaining soil pH and soil fertility
levels and making certain that the defoliation regime
does not favor broomsedge plants.
One of these steps alone may not eliminate a thick
stand of established broomsedge , or do so only very
slowly. However, tipping the competitive edge toward
forage species and away from
broomsedge will be effective in the long run. Planting
forage crop seed may also be necessary if there are
not enough forage plants present to recover a good