What Are the Key Differences Between Dallisgrass and Crabgrass?
Dallisgrass and Crabgrass are both warm-season grassy weeds, but they grow differently. Knowing these distinctions helps with control.
Dallisgrass is a perennial weed; it comes back each year from its roots and underground stems.
Crabgrass, though, is an annual. It grows from seed in spring, lives one season, and dies when frost arrives. This core difference in their life cycles shapes how we manage them.
How Do Their Growth Patterns Compare?
Dallisgrass grows in thick, round clumps, shooting up tall from a central point. It spreads fast, pushing up quickly between lawn cuttings. Crabgrass lies flat, shaped like a star, with stems reaching out low to the ground. Left alone, it makes a messy, star-shaped mat – sometimes a foot wide or more.
Their seed heads look different too. Dallisgrass has bigger seed heads, with little black specks on them. Crabgrass has very thin, finger-like seed heads that fan out from the top of its stem.
What Are the Differences in Their Root Systems?
Dallisgrass has a thick, deep root system, reaching 12 inches or more into the soil. Short rhizomes help it spread. This robust root structure keeps the plant coming back year after year.
Crabgrass, on the other hand, only has shallow roots. It often proves less persistent and a lot easier to pull up by hand. Because of its deep roots, dallisgrass is tough to control – especially in compacted or heavy clay soils.
What Are Their Life Cycles?
Dallisgrass is a perennial, living over two years and coming back from its roots each spring. It stays green through most of the year here in North Texas.
Crabgrass is different; it’s an annual. Seeds sprout in spring once the soil hits 60 – 65°F. That plant then dies off after the first hard frost. Knowing this life cycle difference helps with control.
What Are Their Distinct Colors and Textures?
Dallisgrass grows in thick clumps, its coarse blades a grayish-green or pale green. These wide blades stand tall and feel rough.
Crabgrass has lighter green or bluish-green leaves, much flatter and broader. It stays closer to the ground, with a texture that can be smooth or a little hairy.
What Is Dallisgrass?
Dallisgrass – Paspalum dilatatum – is a warm-season perennial grass. Many people consider it one of the toughest weeds. This plant grows aggressively, forming thick, round clumps from a central spot. It spreads using short rhizomes and makes a lot of seeds.
You can spot it by its coarse, wide, grayish-green blades. It also has tall seed heads with small, dark, round specks. Its roots go deep, sometimes 12 inches or more, which makes it hard to get rid of. Dallisgrass likes disturbed, compacted, or poor soil. It also grows well in different climates, making it a real problem for turfgrass and general lawn care. Look for visible circular clumps of coarse leaves that stick out from the rest of your lawn.
What Is Crabgrass?
Crabgrass (Digitaria species) is a common annual grassy weed. It prefers warm weather, sprouting in spring and dying off with the first hard frost. This plant spreads low to the ground in a star shape, with stems growing out from a central point.
Often lighter green or bluish-green than the lawn-grass you want, crabgrass has smooth or slightly hairy blades. Each stem’s top fans out with distinctive, finger-like seed heads. You will usually find it in thin or bare lawn spots that get a lot of sun. Does it sound familiar? This makes it a very common lawn weed. It is also easier to control than Dallisgrass, especially if you get those pre-emergent herbicides down on time.
How to Control Dallisgrass and Crabgrass Effectively?
Dallisgrass and crabgrass each need different control strategies. Why? Their life cycles and growth habits vary.
We tackle crabgrass with a solid weed control program, mostly putting down pre-emergent herbicides in early spring, right before it sprouts. Has it already popped up? Then post-emergent herbicides get the job done.
Dallisgrass is tougher. This perennial has deep roots, making it hard to kill off. Pre-emergents won’t touch established dallisgrass. Often, you’ll need several rounds of selective post-emergent herbicides. If things get really bad, you might have to physically remove it or lay new sod. Remember, specific herbicides are key for these grassy weeds – many broadleaf killers won’t work and could damage your other plants.
How to Prevent Dallisgrass and Crabgrass Infestations?
Keeping your lawn thick and healthy is the best defense against dallisgrass and crabgrass. Stop crabgrass before it starts: put down a pre-emergent herbicide every early spring, specifically before the soil warms to a steady 55°F. Dallisgrass is tougher. Its deep roots and perennial nature make prevention difficult.
So, how do you keep these weeds out?
Mow high. A cutting height of 3.5 to 4 inches shades out weed seeds and builds a thicker lawn. Fertilize with organic products; they feed your grass and help it crowd out weeds. Water deeply – at least 1.5 inches weekly – to push roots deeper and make the lawn hardier.
Aerate yearly to break up compacted soil. This helps deter dallisgrass and keeps the whole lawn healthier. Overseed each fall. This fills in bare spots, leaving nowhere for crabgrass to sprout.
Pre-emergents work wonders for crabgrass in early spring; you’ll often need two applications for full coverage.
Finally, keep up with lawn care. Cleaning your mower, for instance, stops dallisgrass seeds and other weed bits from spreading. If you need more help, local lawn care experts can create a specific plan to keep your lawn weed-free.