Crabgrass or Quackgrass?

We had a customer that thought he had a lawn full of crabgrass even after applying a crabgrass preventer. Turns out what he had was quackgrass and it can easily be confused with crabgrass. Being able to differentiate between the two will help you effectively treat and prevent both. Here's what to look for:

Crabgrass

Quackgrass

Crabgrass:

  • A summer annual
  • Spreads by seed
  • Branching and flat
  • Reddish purple stems
  • Small shallow roots
  • Use a pre-emergent in early spring.
  • Don't mow the lawn shorter than 3".
  • Keep your lawn full and healthy as crabgrass will thrive in hot, dry, compacted soil.

Quackgrass:  

  • A perennial grass
  • Spreads by seed and rhizomes through the root system
  • More upright than crabgrass
  • Green stems
  • Large fibrous root system
  • There is no easy way to eradicate quackgrass.
  • The best bet is to get it early before it spreads.
  • Use a non-selective herbicide, like Round-up, which will kill all vegetation in the application area.
  • Pulling quackgrass out will not be effective, as rhizomes in the soil can germinate long after the plant has been removed.