Crabgrass vs. Centipede: How to Identify What’s Actually Growing
Crabgrass grows in a low, spreading, star-shaped pattern with wide, coarse blades and thick stems that root wherever they touch soil, while Centipede grass — the most common lawn grass in Wilmington — has a finer, more uniform texture with a distinctly lighter apple-green color. The clearest test: crabgrass stems are noticeably thicker and often reddish or purplish at the base, while Centipede’s stems stay thin and green throughout.
Why This Mix-Up Happens So Often
Both grow low to the ground, both can appear in patches within an otherwise established lawn, and both have a lighter green color than some other turf types — which makes them genuinely easy to confuse at a glance, especially for homeowners who moved to the area from somewhere with different common grass types. Getting the identification wrong matters, though: treating actual Centipede grass with a broadleaf or grassy weed killer can seriously damage or kill the lawn you’re trying to protect.
The Growth Pattern Test
- Crabgrass grows outward from a central point in a low, radiating, almost star-like pattern — individual crabgrass plants have a distinctly different shape than the surrounding uniform turf, which is often the first visual clue something’s off. Centipede grass, by contrast, spreads more uniformly across the lawn through above-ground stolons, creating an even carpet rather than individual star-shaped clumps standing out from their surroundings.
The Stem and Node Test
This is the most reliable physical check. Crabgrass stems are noticeably thick, often with a reddish or purplish tint near the base, and root readily at each node where the stem touches soil — which is part of why it spreads so aggressively once established. Centipede grass stems stay thin and consistently green, without that reddish base coloring, even as the plant spreads.
The Timing Test
Crabgrass is an annual weed that germinates specifically when soil temperatures warm in spring, typically once soil hits around 55–60°F for several consecutive days — in the Wilmington area, this usually lands sometime in March. If you’re seeing new growth appearing in early spring in patches that weren’t part of your established lawn the previous fall, that timing itself is a strong crabgrass indicator. Centipede grass, as an established perennial lawn, doesn’t show this same sudden new-patch germination pattern — it simply resumes growth from where it already existed.
The Color and Texture Test
Centipede grass has a somewhat coarse but very uniform, light apple-green color across the whole lawn. Crabgrass tends to be a slightly different shade — often a touch more yellow-green — and the individual blade width is usually wider and less uniform than surrounding Centipede turf, giving crabgrass patches a slightly rougher, less consistent texture even from a short distance.
What This Means for Treatment
- If you’ve confirmed crabgrass through the tests above, pre-emergent weed control timed to before spring germination is far more effective than trying to treat it after it’s already established — once mature, crabgrass requires a different, more targeted post-emergent approach that’s less reliable and can affect surrounding turf if not applied carefully.
- If what you’re looking at turns out to be Centipede grass simply establishing in a previously bare or thin section — which can look uneven and different in texture from mature turf nearby during its first season — the correct approach is patience and proper fertilization support, not weed treatment.
When You’re Still Not Sure
Pull a small sample and look at the root system. Crabgrass has a relatively shallow, fibrous root system without the below-ground rhizomes Centipede develops as it matures. If in doubt, a phone photo of a close-up sample — including the stem base and a few inches of root — is usually enough for a quick professional identification before you commit to any treatment.