Crabgrass vs tall fescue: how to tell them apart

This is one of the most common misidentifications in lawn care. Homeowners spray what they think is crabgrass and end up killing their own grass. Or they leave crabgrass alone thinking it is part of their lawn. Here is how to tell them apart.

Growth habit

Crabgrass grows flat and spreads outward from a central point in a star pattern, hugging the ground. Tall fescue grows upright in a bunch-type clump. If the grass is lying flat and radiating outward, it is almost certainly crabgrass.

Blade texture

Crabgrass blades are wider, thicker, and lighter green than fescue. They have a slightly waxy or shiny surface. Tall fescue blades are narrower, darker green, and have prominent veins running parallel along the blade. Feel the blade between your fingers — crabgrass feels coarser.

Timing

Crabgrass is an annual that appears in late spring to early summer and dies at first frost. If a suspicious clump appeared in June and was not there in April, it is likely crabgrass. Tall fescue is a perennial that is present year-round, though it may go dormant and look thin in summer heat.

The pull test

Grab the clump and pull. Crabgrass pulls out easily because it has shallow roots. Tall fescue has a deep root system and resists pulling. If it comes out with minimal effort, it is crabgrass.

What to do about each

For crabgrass: spot-treat with a post-emergent crabgrass killer containing quinclorac. For clumpy tall fescue in an otherwise fine-bladed lawn: dig it out and reseed the spot. For a tall fescue lawn with crabgrass: pre-emergent in spring prevents it from coming back next year.

Grasslytics can identify grass types and weeds from a photo scan. Snap a picture of the suspicious patch and get an instant ID.