1 / 10

Paspalum dilatatum

Dallis grass

Poaceae Subtropical South America

Drought Tolerant

SunFull Sun – Part Shade

WaterMedium · drought-tolerant

HardinessZones 7–11

Overview

Paspalum dilatatum is a coarse, deep-rooted perennial bunchgrass in the family Poaceae, forming dense tufts 1.5-5 feet (45-150 cm) tall from short rhizomes. The flat leaf blades are 4-12 inches (10-30 cm) long and up to 0.5 inch (12 mm) wide, medium green, with a prominent membranous ligule where blade meets sheath. In summer and fall it sends up flowering stems bearing 3-7 spreading racemes arranged along the upper stalk, each lined with rounded spikelets edged in long silky hairs. Dark anthers and stigmas give the seed heads a flecked appearance. P. dilatatum is native to subtropical South America but has naturalized across warm-temperate regions worldwide, where it is grown as a pasture and forage grass and also spreads as a weed of lawns, turf, and roadsides. Its rapid summer growth and tall seed stalks make it conspicuous in mown turf. Seed heads are commonly infected by the ergot fungus Claviceps paspali, which forms hardened dark bodies toxic to grazing livestock. The grass tolerates heat, periodic flooding, and drought once its deep root system is established, but it is killed back by hard frost.

Native Range

Native to subtropical South America, centered in Argentina, Uruguay, southern Brazil, and Paraguay. It has been widely introduced and naturalized in warm-temperate and subtropical regions of North America, Australia, Africa, Asia, and southern Europe, where it grows in pastures, lawns, ditches, and disturbed ground.

Suggested Uses

Grown as a warm-season pasture and forage grass on farms in subtropical and warm-temperate regions. It also stabilizes soil on banks and in ditches that flood periodically. In managed lawns and sports turf it is treated as a weed rather than a planted species.

How to Identify

Recognized by its coarse tufted habit and tall flowering stalks carrying 3-7 spreading racemes along one side of the stem. The rounded spikelets are arranged in rows and fringed with long silky hairs, giving the seed head a hairy edge under magnification. Dark purple-black anthers and stigmas protrude during flowering. A ring of hairs at the stem nodes and a tall membranous ligule help separate it from related Paspalum spp. species and other warm-season grasses.

Appearance

Size & Dimensions

Height1'6" - 5'

Width/Spread1' - 2'

Colors

Flower Colors

green

purple

Foliage Colors

green

Bloom Information

Bloom Period

~18 weeks

Summer Fall

Flowering stems appear from early summer into fall, mainly June through October in warm climates. The grass flowers repeatedly through the warm season as new culms rise above the foliage. Flowering slows in drought and stops with the first frost.

Detailed Descriptions

Flower Description

green to purplish with dark anthers

Foliage Description

medium green

Growing Conditions

Sun Requirements

SunFull Sun SunPartial Shade

Requires 6-12 hours of direct sunlight daily

• Full Sun: 6+ hours of direct sunlight

• Partial Shade: 3-6 hours of direct sunlight

• Full Shade: Less than 3 hours of direct sunlight

Soil Requirements

pH Range5.5 - 7.5(Neutral)

357912

Soil Types

clay loam sand

Drainageaverage

Water & Climate

Water Needs

Medium

Frost Tolerance

tender

Time to Maturity

establishes within one season

Drought Tolerance

Drought tolerant when established

Care & Maintenance

Care Guide

Paspalum dilatatum grows in full sun to light shade on a wide range of soils, from heavy clay to sand, and tolerates both periodic flooding and drought once established. It grows in pH from about 5.5 to 7.5 and responds to summer warmth and moisture with rapid growth. In lawns and turf it is treated as a weed because its fast-growing seed stalks outpace mowing and its coarse clumps disrupt finer turf. It is hardy in roughly USDA zones 7 to 11 and dies back in cold winters, regrowing from the crown in spring. Seed heads can carry the ergot fungus, a concern where the grass is grazed. Frequent close mowing weakens but rarely eliminates established clumps.

Pruning

Mowing or cutting the tall seed stalks through the growing season limits seed spread and keeps clumps low. In pasture, grazing or cutting before seed heads mature reduces ergot risk. Dead foliage can be cut back in late winter before new growth resumes.