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Low Spear Grass Poa annua

Previously known as:

  • Poa annua var. aquatica
  • Poa annua var. reptans
Phonetic Spelling
POH-ah AN-yoo-uh
Description

Annual bluegrass, in the family Poaceae, is a winter annual, clump-forming grass with a yellow-green color, prow-shaped leaf tips, and a distinctive whitish flower head. It is primarily a weed of lawns and turfgrass.  Preferring moist, shady areas, it emerges from fall through spring, flowers, and then dies with the onset of warm weather. Annual bluegrass is a prolific seed producer but is well managed by most preemergence herbicides labeled for use. 

It can be a difficult weed to control, as each plant produces several hundred seeds in a season that can lay dormant years before sprouting.  

 

See this plant in the following landscape:
Cultivars / Varieties:
Tags:
#vigorous#weed#weedy#winter annual weed#annual weed#bluegrass
 
Cultivars / Varieties:
Tags:
#vigorous#weed#weedy#winter annual weed#annual weed#bluegrass
  • Attributes:
    Genus:
    Poa
    Species:
    annua L.
    Family:
    Poaceae
    Life Cycle:
    Annual
    Recommended Propagation Strategy:
    Seed
    Country Or Region Of Origin:
    P. annua is native to temperate areas of Eurasia.
    Distribution:
    P. annua is a cosmopolitan grass that is listed as one of the most aggressive weeds invading areas from sea level up to 1200 m in elevation. It can be found from the Arctic to the Antarctic regions in practically all terrestrial ecosystems. It is listed as a weed in 38 crops in more than 80 countries within and outside its native distribution range. It grows in a wide variety of soils, tolerates trampling, mowing, and frozen conditions, and is a frequent weed in areas heavily trafficked by livestock or humans. This species has the potential to outcompete other plants and crops. The list of countries in which this species now occurs may not be complete, as P. annua has spread to almost all areas of the world where temperate and subtropical crops are grown, and to some relatively undisturbed habitats.
    Fire Risk Rating:
    low flammability
  • Whole Plant Traits:
    Plant Type:
    Weed
    Habit/Form:
    Clumping
    Erect
    Growth Rate:
    Rapid
    Maintenance:
    Low
    Texture:
    Fine
  • Cultural Conditions:
    Light:
    Partial Shade (Direct sunlight only part of the day, 2-6 hours)
    Soil Texture:
    Clay
    Loam (Silt)
    Sand
    Soil pH:
    Acid (<6.0)
    Neutral (6.0-8.0)
    Soil Drainage:
    Good Drainage
    Available Space To Plant:
    Less than 12 inches
    NC Region:
    Coastal
    Mountains
    Piedmont
    USDA Plant Hardiness Zone:
    4a, 4b, 5b, 5a, 6a, 6b, 7a, 7b, 8b, 8a
  • Fruit:
    Fruit Type:
    Achene
  • Flowers:
    Flower Color:
    White
    Flower Inflorescence:
    Panicle
    Flower Bloom Time:
    Spring
    Flower Shape:
    Irregular
    Flower Size:
    < 1 inch
    Flower Description:
    The spikelets are stalked, awnless, 1 to 2 cm (3/8 to 3/4 in.) long when flowering, and loosely arranged on delicate paired or spreading branches.
  • Leaves:
    Leaf Color:
    Green
    Leaf Feel:
    Smooth
    Leaf Arrangement:
    Alternate
    Leaf Shape:
    Linear
    Leaf Margin:
    Serrate
    Hairs Present:
    No
    Leaf Length:
    3-6 inches
    Leaf Width:
    < 1 inch
    Leaf Description:
    The leaves are flat, slightly keeled with characteristic 'tramlines'. The leaves are smooth and abruptly contracted at the apices to give a characteristic 'boat-shaped tip'. A further characteristic is that the leaves are often transversely wrinkled. The leaves are folded in the sheath which is smooth and somewhat compressed. Screen reader support enabled.
  • Stem:
    Stem Is Aromatic:
    No
  • Landscape:
    Problems:
    Weedy