How to Kill Blue Grass


Annual bluegrass (Poa annua) occurs across the United States. It infests gardens, ornamental beds and turfs. The grass begins germination when soil temperatures fall below 70 degrees F in spring or fall. It attains a height of 6 to 8 inches. It grows well in moist soils and will not tolerate drought. Seed heads develop when the grass reaches six weeks of age. The seed production persists throughout the growing season, but is most prolific in the spring. A plant has the capability of producing 100 seeds in only eight weeks. Mowing offers little seed control because seeds emerge within a few days of pollination.

Step 1

Avoid over-watering to kill shallow-rooted blue grass. Most turf grasses and ornamental plants can withstand a brief period of drought, and the stress it induces, but the blue grass is unable to tolerate drought well.

Step 2

Apply a preemergent herbicide to kill seeds, such as prodiamine, benefin, pendimethalin, bensulide, dithiopyr or oxadiazon, before blue grass seed germination in late summer or early fall. Reapply the preemergent herbicide in mid-March or mid-April. Follow the directions on the label for application instructions. Use when the soil temperature dips below 70 degrees F.

Step 3

Hand pick blue grass from ornamental beds before seeding. Promptly dispose of the pulled plants.

Step 4

Spray blue grass using glyphosate or glufosinate in select spots. Follow the directions on the label for application. Take care not to let the herbicide come into contact with ornamental or native plants because the herbicide will kill them.

Things You'll Need

  • Preemergent herbicide
  • Herbicide


  • University of California: Annual Bluegrass
  • Ohio State University: Annual Bluegrass and Rough Bluegrass Control
  • Michigan State University: A Selective Annual Bluegrass
  • Purdue University: ID and Control of Annual Bluegrass

Who Can Help

  • Washington State University: Annual Blue Grass
Keywords: blue grass control, killing blue grass, blue grass infestation

About this Author

Kimberly Sharpe is a freelance writer with a diverse background. She has worked as a Web writer for the past four years. She writes extensively for Associated Content where she is both a featured home improvement contributor (with special emphasis on gardening) and a parenting contributor. She also writes for Helium. She has worked professionally in the animal care and gardening fields.