Dallisgrass

Overview

Dallisgrass (Paspalum dilatatum) is a major warm-season perennial grassy weed in zones 7-10. It forms coarse, fast-growing clumps that disrupt the uniformity of bermuda, zoysia, and St. Augustine lawns. It is one of the most difficult warm-season weeds to control because no effective selective herbicide is currently available for homeowners.

Identification

Coarse-textured, clumping grass that grows in circular, expanding patches. Produces tall, distinctive seed stalks with dark seeds arranged along finger-like branches (racemes). The seed heads appear within days of mowing, making dallisgrass patches highly visible. Blades are wider and coarser than bermuda or zoysia.

Damage to Your Lawn

Dallisgrass grows faster than surrounding warm-season turf, producing unsightly seed heads that stick up above mowing height within 2-3 days. Circular patches expand outward each season as short rhizomes push into new territory. The coarse texture and rapid growth rate create an uneven, patchy appearance.

Control Strategy

This is one of the hardest warm-season weeds to eliminate. MSMA was the historical standard treatment but is now restricted for residential use in most states.

The most practical approach for homeowners is spot-treatment with glyphosate (non-selective) to kill individual clumps, followed by plugging or reseeding the treated areas. For bermuda lawns, the surrounding grass will fill in killed spots relatively quickly.

Manual removal works for small, isolated patches — dig out the entire clump including all rhizomes. This may need to be repeated over multiple seasons as fragments regrow.