Dormancy

    Annual Bluegrass

    Poa annua

    Annual Bluegrass

    Annual bluegrass (Rasbak, Wikimedia Commons)

    Annual Bluegrass

    Annual bluegrass sheaths and ligules (Rasbak, Wikimedia Commons)

    Annual Bluegrass

    Annual bluegrass flower heads (James Lindsey, Wikimedia Commons)

    Description

    • tufted; upright growth (up to 1 foot tall); leaves emerge from protective sheath with pointed and papery ligule
    • narrow leaves (1 – 4 inches long, 1/16 – 3/16 inch wide); short flower heads (1 – 4 inches high) bear 3 to 6 seeds per branching stalk; light green in color

    Location

    • common in lawn areas and planting beds

    Life Cycle

    • winter annual or short-lived perennial grass: seedlings germinate when soil temperatures are below 70°F in late summer, early fall or early spring
    • plants flower within 8 weeks of germination and continue to flower and produce seeds until the onset of hot temperatures in summer months
    • dormant plants produce new blade growth during cool fall temperatures

    IPM Recommendations

    • Annual bluegrass is difficult to control in lawn areas since it commonly produces seed close to the soil surface (flower heads cannot be mowed off like many other turfgrass weeds).
    • Maintain maximum turfgrass vigor through appropriate management practices; deep, infrequent irrigation will reduce seedling germination in lawn areas.
    • Hand-pull plants in lawn areas prior to flowering.
    • Apply appropriate pre-emergent herbicide prior to seed germination.