Johnsongrass or Vaseygrass?


Ag Biz News Column
By: Chad Gulley
County Extension Agent–Ag/NR
Smith County


Johnsongrass or Vaseygrass


Do you have Johnsongrass in your pasture or hayfield?  Do you know the difference between Johnsongrass and other tall perennial grass species in your fields like Vasey grass?

Johnsongrass is originally native to the Mediterranean region and was introduced into the United States in the early 1800’s as a forage species.  Johnsongrass (Sorghum halepense) is a tall, perennial grass species that grows in dense clumps or nearly solid stands.  This grass species can reach up to 8 feet in height, but usually is in the 3 to 6 feet tall range.  The leaves are smooth, lanceolate shape with a white mid vein.  The stem can be a pink to rusty red color near the base of the plant.  The flowers are large, loosely branched purplish hairy panicles.  The seed are reddish-brown and nearly 1/8 of an inch long.  This grass species reproduces vegetatively and is a prolific seed producer as well.

Johnsongrass occurs in crop fields, pastures, abandoned fields, right-of-ways, forest edges, ditches, and wetlands.  It can thrive in rich bottom ground especially areas that have been cultivated.  It is listed as a noxious weed in many states.  It can be toxic to livestock under the right conditions.  Once started in an area, it is hard to control.

Johnsongrass may cause nitrate poisoning, prussic acid poisoning, and interstitial cystitis like other sorghum varieties under certain favorable conditions to livestock species.  Sorghum forages under the stress of rapid growth, drought, or freshly frosted plants in the fall can generate cyanogenic glycosides.  These can lead to issues for our livestock if not monitored.

Vasey grass (Paspalum urvillei Steud) is another tall perennial grass species that grows in clumps around East Texas as well.  Vasey grass was introduced into the United States from South America as a forage species.  Vasey grass can also grow from 3 to 6 feet tall in height.  The leaves are densely haired at the stem.  The seed head is long with 12 to 25 spikelets resembling that of Dallisgrass.  The seed heads also appear fuzzy with short hairs and the seeds are a rust color when mature.  Vasey grass too has a white mid vein down the leaves.

Vasey grass can be found in pastures and hayfields, in areas for erosion control, and for wildlife habitat.  For wildlife, this plant primarily provides cover though some birds and small mammals may use the seeds.  One difference in Vasey grass is the seed heads tend to lay over some like Dallisgrass as opposed to Johnsongrass seed heads staying upright on the end of the stem.

So how do I control Johnsongrass or Vasey grass in my pastures or hay fields?   Control includes cultural practices such as mowing, tilling, hand pulling of the grass in light infestations, and even chemical control.  Chemical controls for Johnsongrass include products like glyphosate, sulfosulfuron, and nicosulfuron/metsulfuron methyl.  Be sure to read the label and follow all label recommendations when using any pesticide.

Both of these grass species can be used as a forage species and for hay in East Texas.  In a hay field, these two grass species may take a little longer to cure or become dry enough to bale.  Since Johnsongrass spreads by seed as well vegetatively, control will be harder.  If you suspect any issues with these grass species in your hay, laboratories that test the quality of the hay or forage species can determine nutritive as well as any toxicity values of the forage species.

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