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

    • Hand-pull plants prior to seed maturation.
    • Apply a mulch layer 3 inches deep on planting beds to reduce seed germination.
    • Apply an appropriate pre-emergent herbicide prior to seed germination or spot treat foliage with an appropriate post-emergent herbicide.