Dallisgrass vs. Crabgrass: Key Differences and Control Tips

When it comes to lawn weeds in North Texas, two of the most common offenders are dallisgrass and crabgrass. At first glance, they may appear similar, since both form coarse clumps and spread quickly across thin or stressed lawns. However, their growth habits, life cycles, and control strategies are very different. Misidentifying one for the other often leads to wasted time, money, and treatments that do not work.

For homeowners in Keller, Southlake, and Fort Worth, understanding the differences between these two weeds is essential for choosing the right management plan.

This guide explains how to distinguish between dallisgrass and crabgrass, why each is such a challenge for North Texas lawns, and the most effective ways to control them.

Understanding the Basics

Crabgrass

• Annual life cycle: Crabgrass is an annual grassy weed, meaning it completes its life cycle within one growing season. It germinates in spring when soil temperatures reach around 55°F, spreads aggressively through the summer, and dies with the first frost.

• Seed production: Before it dies, each crabgrass plant produces thousands of seeds that remain dormant in the soil and sprout the following spring, ensuring ongoing outbreaks without prevention.

• Appearance: Forms low, sprawling clumps that spread outward like crab legs, often lighter green than surrounding turf.

Dallisgrass

• Perennial life cycle: Dallisgrass is a perennial grassy weed, which means it survives from year to year. It spreads not only by seed but also by underground rhizomes, making it much more difficult to eradicate than crabgrass.

• Persistence: Unlike crabgrass, dallisgrass does not die off in winter. It re-emerges every spring, growing taller and coarser than most turfgrasses.

• Appearance: Forms coarse, upright clumps with seed stalks that often have black specks (fungal sclerotia). These stalks grow quickly, making dallisgrass stand out in a manicured lawn.

Identification: Dallisgrass vs. Crabgrass

Although both weeds form clumps and compete aggressively with turfgrass, there are distinct differences that make it possible to tell them apart. In Keller, Southlake, and Fort Worth, knowing these differences helps homeowners choose the right treatment strategy.

Crabgrass

• Growth habit: Low-growing clumps that sprawl outward close to the ground, resembling crab legs.

• Leaf color: Wide, lighter green leaves that contrast with darker turfgrass.

• Seasonality: Germinates in late spring, thrives during hot summer months, and dies after the first frost.

• Seed heads: Produces seed heads in late summer, ensuring thousands of seeds remain in the soil for the next season.

Dallisgrass

• Growth habit: Coarse-textured clumps that stand upright and disrupt the smooth appearance of turf.

• Seed heads: Tall stalks with distinct black specks, known as fungal sclerotia, which make it easy to identify.

• Spread: Reproduces through both seed and underground rhizomes, allowing it to expand more aggressively than crabgrass.

• Seasonality: Unlike crabgrass, dallisgrass does not die off in winter. It stays green well into fall and re-emerges every spring.

Learn more about crabgrass and other invasive weeds in our Texas Weed Identification Guide.

Why They’re a Problem in North Texas Lawns

Both crabgrass and dallisgrass thrive in the clay-heavy soils and hot climate of North Texas. While they may look similar, the problems they create for homeowners are slightly different:

• Crabgrass: Spreads rapidly in thin or stressed turf, filling bare spots and reducing curb appeal. Because it is lighter in color and lower growing than Bermuda or St. Augustine, it leaves lawns looking patchy and uneven.

• Dallisgrass: Forms large, coarse clumps that stand out sharply against fine-textured grasses like Bermuda or St. Augustine. Over time, its upright growth and persistence crowd out desirable turf and create a bumpy, irregular surface.

Since dallisgrass is perennial, it is generally considered more difficult to eliminate than crabgrass. Once established, it requires multiple treatments and consistent monitoring to keep under control.

How to Control Crabgrass

Because crabgrass is an annual weed, prevention is the key to keeping it out of North Texas lawns.

Best practices include:

• Apply pre-emergent herbicides in spring before soil temperatures reach 55°F to stop seeds from sprouting.

• Mow at the proper height for your turf type to shade soil and reduce seed germination.

• Fertilize and overseed thin areas to maintain dense turf that naturally crowds out crabgrass.

• Spot treat with post-emergent herbicides once plants appear to prevent further spread.

Protect your yard with our Fertilization & Weed Control programs designed for North Texas lawns.

How to Control Dallisgrass

Because dallisgrass is a perennial weed, control requires more persistence and effort than crabgrass. Its underground rhizomes and prolific seed heads make it especially hard to remove completely.

Best practices include:

• Spot treat with selective herbicides designed for perennial grassy weeds to minimize turf damage.

• Dig out small infestations, making sure to remove roots and rhizomes to prevent regrowth.

• Mow frequently to remove seed heads before they mature and spread.

• Maintain dense turf with fertilization and overseeding so grass competes with dallisgrass.

• Consider professional treatments for large or stubborn infestations that resist homeowner efforts.

For more expert recommendations, visit the Texas A&M Weed Identification Guide.

Prevention Strategies for Both Weeds

Although crabgrass and dallisgrass require different treatment approaches once they appear, the best way to manage both is through lawn health and prevention. A strong, dense lawn naturally resists weed pressure by leaving little room for invaders to establish.

Key prevention practices include:

• Keep soil aerated: Annual aeration reduces compaction in North Texas clay soils, improves drainage, and allows turfgrass roots to grow deeper and stronger.

• Follow a seasonal fertilization plan: Balanced feeding keeps turf thick and competitive, leaving fewer opportunities for weeds to spread.

• Water deeply but infrequently: Encourages deep root growth and prevents shallow, stressed turf that weeds can exploit.

• Repair thin or bare areas with overseeding: Filling in open patches ensures turf density and limits the bare soil space where crabgrass or dallisgrass can take hold.

See how our Residential Lawn Care services prevent recurring weed problems through professional fertilization, overseeding, and ongoing monitoring.

Final Thoughts

Though often confused, crabgrass and dallisgrass require very different strategies for control. Crabgrass is an annual weed that can be effectively managed with consistent pre-emergent herbicide applications and healthy turf practices. Dallisgrass, on the other hand, is a perennial weed that demands persistence, selective herbicides, and cultural improvements such as aeration and overseeding.

At Conroy’s Lawn and Landscape, we provide customized weed control programs designed for the unique challenges of Keller, Southlake, and Fort Worth lawns. Our professional care ensures your turf stays healthy, uniform, and weed-free year after year.