Dallisgrass
Paspalum dilatatum · Warm-season, Perennial, C4 grass
AI-generated identification · may be incorrect
Grass Category
Invasive/Weed Grass, Pasture/Forage Grass, Erosion Control
Hardiness Zones
Thrives in USDA Hardiness Zones 7 through 10. Exhibits good heat tolerance, moderate cold tolerance (surviving winter dormancy as underground rhizomes), and is a prominent weed issue in the transition zone.
Grass Family
Poaceae, subfamily Panicoideae, tribe Paniceae
Variety / Cultivar
Common Dallisgrass (no specific named turf cultivars as it is generally considered a weed in lawns)
About This Grass
Dallisgrass grows in coarse, sprawling clumps with a flattened, basal rosette appearance before sending up tall, upright flowering stems. Unmowed height can reach 2 to 4 feet. The foliage is a light to medium green color, often with a slightly grayish or blue-green tint. The texture is coarse, and the overall density is relatively loose in turf settings. The notable seed head features a long terminal stalk bearing 2 to 7 alternate, hairy-based spikes (racemes) containing fuzzy, oval-shaped spikelets.
Blade Characteristics
Blades are coarse, typically 3 to 10 mm wide, flat, and feature a pointed tip. The color is light to medium green. Vernation is folded in the bud. The texture is generally hairless on the blade surface, though long hairs are frequently present near the collar region and base of the leaf blade. The ligule is a distinct, tall, membranous structure (up to 3 mm long), auricles are absent, and the collar is broad and continuous.
Root System
Features a deep, robust fibrous root system accompanied by short, scaly rhizomes. It has a moderate to fast establishment rate from seed and underground structures. It does not typically form a uniform turf sod, instead creating patchy, coarse clumps. Its deep roots provide excellent drought survival capabilities and make manual removal difficult.
Growing Information
Origin Region
Native to South America (Brazil and Argentina); introduced globally and naturalized in warm, temperate, and subtropical regions worldwide, including the southeastern and western United States.
Growth Habit
Bunch-type forming wide, coarse clumps, but capable of expanding slowly via short, thick rhizomes to form localized patches.
Sunlight & Water Needs
Requires full sun for optimal growth, tolerating very light partial shade. It thrives in moist, poorly drained soils, highly compacted soils, and frequently irrigated turfgrass, but exhibits good drought tolerance by going semi-dormant during dry spells. Prefers heavy, clay soils and tolerates a wide pH range.
Mowing & Maintenance
In managed turf, it survives low mowing by growing prostrate leaves beneath the mower blade height, but frequent mowing fails to control it due to its rapid upward growth of seed stalks. Requires high maintenance to manually dig out clumps or selective herbicide applications, as standard mowing only forces it to grow horizontally.
Special Characteristics
Extremely low traffic/wear tolerance in terms of aesthetic quality because its coarse, prostrate leaves ruin uniform turf, though the plant itself survives heavy compaction. Resistant to many common turf diseases. High drought recovery from underground reserves. Considered an aggressive, unsightly weed in fine lawns due to its fast-growing, coarse seed stalks.
Ecological Information
Introduced species in North America. While often classed as a noxious weed in turfgrass management, it serves as a palatable forage grass for livestock in pastures. It provides some soil stabilization in erosion-prone areas but tends to outcompete desirable turf grasses in wet or compacted soils.