Dallisgrass,-Grass Family

Paspalum dilatatum,

Characterisitcs. This is a perennial grass that was introduced into the United States from South America and is currently spread throughout much of the southern half. With limited use as forage it is a primary pest in moist areas such as turf, alfalfa hay fields, wet roadside areas, irrigation ditch banks, and in some orchards and vineyards. Reproduction is by seed with germination occurring throughout the year depending on conditions. Rhizomes also add to the rapid spread of this pest. Besides forming unsightly clumps in turf the stiffness and texture of these clumps present a hazard (from tripping) in sports fields. Dallisgrass grows faster than other species of turf grasses adding to its status as a major pest. The flowering shoots are often bent over rather than being cut by lawn mowers and springs back up again adding to its pestiferous status.

Identifying Characteristics. This coarse grass grows in clumps that slowly spread via short rhizomes. As the clump matures, the center may die and a different grass or weed may be growing in its center. In areas of large numbers of Dallisgrass plants, they grow together forming almost a solid planting with uneven texture and poor turf grass qualities. Leaf blades are flat, 2 to 4 inches long, smooth without hairs and are produced in abundance at the base of the plant.

The flowering stalk grows 14 to 65 inches tall and frequently has a purplish coloration at the base. The flower head consists of 2 to 10 racemes (branches near the top of the flowering stalk) that arise from different points along the flower stalk and are often drooping. Each raceme has 2 rows of flat, egg-shaped spikelets, which contain the seed along its entire length. These appear as small black dots along the raceme.

Factors Important in Control. A major component of Dallisgrass management is to prevent new plants from becoming established. In small scale turf it is best to physically remove small plants before rhizomes and seed production develops. Care should be taken to remove all of the plant since leaving any of the rhizomes will frequently result in regrowth. When Dallisgrass is present in abundance or the plants are located over a large area, it may be necessary to supplement cultural practices with herbicides.