Dallisgrass

Dallisgrass (Paspalum dilatatum) is a perennial, warm season grass that readily invades turfgrass areas throughout Texas and the Southeastern states. Dallisgrass is native to South America and was introduced into the U.S. for its value as a forage plant. Records indicate that it was first introduced into the U.S. in the vicinity of New Orleans, Louisiana. It was found in Texas as early as 1875. The grass was named for A.T. Dallis of LaGrange, Georgia, who was an enthusiastic proponent of the plant around 1900.

Description. Dallisgrass grows in clumps, or bunches. Leaves are produced near the base of the plant on shoots that arise from a knotty base of very short rhizomes. Relative to turfgrasses, especially bermudagrass, the leaves of dallisgrass are much coarser textured. Dallisgrass also produces unsightly seedstalks several feet above the turf. After mowing, dallisgrass leaves elongate much faster than bermudagrass turf and significantly increases the mowing needs for bermudagrass turf areas.

Control. In bermudagrass, dallisgrass is effectively controlled by two applications of MSMA or similar materials at 3 pounds per acre. Applications in early spring are most effective and should be repeated at 2-week intervals. MSMA should be applied with a boom or broadcast sprayer in 100 gallons or less of water per acre.

Make applications of MSMA 3 to 4 days after mowing to provide more leaf surface to absorb the herbicide. Do not water for at least 24 hours after treatment and delay mowing for several more days. Dallisgrass leaves will begin to show discoloration 3 to 5 days after treatment and significant leaf burning should be apparent after 7 to 10 days. Within 2 weeks some regrowth may occur and a second application of MSMA is necessary.

In St. Augustine and centipedegrass lawns, spot treatment of dallisgrass with glyphosate (Roundup) is most effective. Treated areas need to be plugged or sodded with St. Augustine or centipedegrass after dallisgrass dies to prevent other weeds from becoming established in the dead areas. Preemerge herbicides may also be helpful in St. Augustine or centipede turf to prevent the spread of dallisgrass from seed.