Quackgrass vs Crabgrass

Quackgrass and crabgrass are two common lawn weeds that can be frustrating for homeowners to control. While they may look similar at first glance, there are some key differences between quackgrass and crabgrass. Understanding how to identify and treat these weeds is important for maintaining a healthy lawn.

Identifying Quackgrass

Quackgrass is a cool-season perennial grass that spreads aggressively through rhizomes. Here are some tips for identifying quackgrass:

  • Leaf blades are bright green and flat with a sharp, pointed tip. Leaves are 1/4 to 1/2 inch wide.
  • Auricles wrap around stem, clasping it.
  • Forms dense patches that can spread several feet per year through underground rhizomes.
  • Light green stems are hollow and smooth.
  • Seed heads have 5-8 spikes, 2-6 inches long.

Controlling Quackgrass

Quackgrass is difficult to control because of its extensive rhizome system. Here are some effective control methods:

  • Hand dig small patches, being sure to remove all roots and rhizomes. This is labor intensive.
  • Use glyphosate (Roundup) carefully on clumps as it translocates to the roots. Several applications may be needed.
  • Promote vigorous lawn growth to compete with quackgrass. Mow high and fertilize moderately.
  • Overseed bare spots with desirable grass seed in the fall.
  • Solarization with clear plastic in summer can help control quackgrass.
  • Consider re-sodding small areas that are heavily infested.

Identifying Crabgrass

Crabgrass is a summer annual grassy weed. Here are tips for identifying crabgrass:

  • Leaf blades are light green, broad, and coarse with blunt ends. Up to 3 inches long.
  • No auricles present where leaf blade meets stem.
  • Forms clumps that can root at lower joints if stems contact ground. Spreads by seed.
  • Stems are pale green, smooth, and often branch into a Y shape.
  • Seed heads have several spikes resembling crab claws.

Controlling Crabgrass

The key to controlling crabgrass is prevention and early intervention:

  • Crabgrass germinates when soil temperatures reach 55-60°F, so apply pre-emergent herbicide in early spring.
  • Pull young crabgrass plants by hand before they establish deep roots.
  • Mow high and fertilize moderately to promote competition from desired lawn grasses.
  • Overseed bare spots with desirable grass seed in fall to thicken lawn.
  • Post-emergent herbicides containing quinclorac, fenoxaprop, or MSMA can help control established crabgrass.
  • Reapply crabgrass preventer in early summer for season-long control.

Key Differences Between Quackgrass and Crabgrass

  • Quackgrass: Perennial that spreads by rhizomes. Crabgrass: Annual that spreads by seed.
  • Quackgrass: Cool-season grass. Crabgrass: Warm-season grass.
  • Quackgrass: Hollow, smooth stems. Crabgrass: Branched, Y-shaped stems.
  • Quackgrass: Clasping auricles. Crabgrass: No auricles.
  • Quackgrass: Aggressive spreader. Crabgrass: Forms clumps.

By understanding the identification, life cycles and control methods for quackgrass and crabgrass, you can make great headway in removing these troublesome weeds from your lawn for good. Proper mowing, fertilization, overseeding, and strategic herbicide use will keep your turf thick and weed-free. With persistence and patience, you can outsmart these invasive grasses.

Frequently Asked Questions About Quackgrass vs Crabgrass

Is quackgrass a grass or a weed?

Quackgrass is considered a weed, even though it is a grass. This cool-season perennial grass is highly invasive and can quickly take over lawns and gardens when left unchecked. Its aggressive rhizomes help quackgrass spread rapidly.

Is crabgrass a perennial or annual?

Crabgrass is a summer annual weed, meaning it germinates from seed every year. Crabgrass dies off with the first hard frost in the fall or winter and does not regrow from root pieces the following spring.

Should I pull crabgrass or use herbicide?

For young crabgrass plants, hand pulling can be effective if done repeatedly over time. Once plants are established, post-emergent herbicides specifically made for crabgrass control often provide the best results. Always follow label directions carefully.

How do I stop quackgrass from spreading?

To stop the spread of quackgrass, you need to kill the entire root system. This can be done through repeated digging and removal of all roots and rhizomes, or by carefully using a systemic glyphosate product. Promoting thick turf growth will also help compete against quackgrass spread.

When should I apply crabgrass preventer?

Crabgrass preventers or pre-emergent herbicides should be applied in very early spring, just before the ground temperature reaches 55-60°F. This timing is crucial to create a barrier that stops crabgrass seeds from germinating.

How can I get rid of quackgrass organically?

Organic methods like solarization, corn gluten meal, or white vinegar can help control quackgrass but may require multiple applications. Hand digging is also organic but extremely labor intensive for quackgrass removal. Maintaining thick, healthy turf is the best organic approach.

What is the best way to identify crabgrass vs quackgrass?

Crabgrass has a blunt leaf tip while quackgrass leaves come to a sharp point. Crabgrass stems branch into a Y-shape, but quackgrass stems are smooth. Also look for the auricles that clasps quackgrass stems right where the leaf blade attaches.


Quackgrass and crabgrass may seem similar when taking over a lawn, but understanding their key differences is half the battle. Quackgrass is a perennial grass with spreading rhizomes, while crabgrass is a summertime annual. Effective control relies on proper identification and utilizing the right tools and timings to stop their spread or germination. With knowledge and persistence, you can rid your lawn of these troublesome weeds.