Smutgrass

Smutgrass (Sporobolus indicus and related species, including giant smutgrass / West Indian dropseed) is a warm-season perennial bunch-type grass that forms dense, coarse, dark-green clumps standing well above mowed turf. The leaf blades are stiff, narrow, and taper to a fine point. Its most distinctive feature is the seedhead: a long, slender, spike-like, contracted panicle held tightly against the stem, which is frequently colonized by a black sooty fungus (the source of the name smutgrass) that coats the seedhead in a dark mass. The combination of a tough bunchy habit and the narrow, dark, smutted seedhead distinguishes it from other clumping grasses.

In turf, smutgrass forms coarse, dark-green clumps that grow faster and taller than the surrounding grass and quickly reappear above the canopy after mowing, producing a lumpy, uneven, weedy texture that ruins uniformity. The dark smutted seedheads add to the unsightly appearance, and dense established clumps crowd out desirable turf and resist routine mowing and ordinary control, progressively degrading the stand.

Smutgrass is a long-lived warm-season perennial bunchgrass that reproduces prolifically by seed, with individual plants capable of producing tens of thousands of seeds per year, and it regrows persistently from its established crown. Seedlings establish in warm conditions, and once a crown is established the plant is deep-rooted, drought-tolerant, and very difficult to dislodge. The heavy seed production and durable perennial crown together make established stands persistent and prone to steady spread.

It is most problematic in warm climates and is favored by warm-season turf and pastures, low-maintenance areas, and sites where the desirable grass is thin or stressed. Smutgrass tolerates close mowing, drought, and a range of soils, and it invades open, thin, or overgrazed/overworn areas where seedlings can establish; once present it spreads outward from prolific seed and is reinforced by its competitive, deep-rooted crowns.