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German Knotweed Scleranthus annuus

Other Common Name(s):

Description

Knawel is a winter annual weed in the pink family that is native to Eurasia and Africa. It has been introduced to much of the USA and Canada. This small plant grows 2-5 inches tall and the spreading and ascending stems can form dense mats. They germinate in winter and grow during warm spells, bloom in early spring and die in late spring or early summer. They spread by seeds.

This weed can grow in a variety of conditions and is often found in disturbed sites, fields and lawns. It prefers sandy and gravelly soils and is drought tolerant but tolerates moist sites and sun to partial shade.

See this plant in the following landscape:
Cultivars / Varieties:
Tags:
#full sun tolerant#drought tolerant#winter annual weed#cool season weed#lawn weed#dry soils tolerant#partial shade tolerant#weed
 
Cultivars / Varieties:
Tags:
#full sun tolerant#drought tolerant#winter annual weed#cool season weed#lawn weed#dry soils tolerant#partial shade tolerant#weed
  • Attributes:
    Genus:
    Scleranthus
    Species:
    annuus
    Family:
    Caryophyllaceae
    Uses (Ethnobotany):
    Has been used in herbal medicine
    Life Cycle:
    Annual
    Country Or Region Of Origin:
    Macaronesia, Europe, Asia, North Africa
    Distribution:
    Eastern, Central and Pacific coast of USA and Canada
  • Whole Plant Traits:
    Plant Type:
    Weed
    Habit/Form:
    Creeping
    Horizontal
    Prostrate
    Spreading
  • Cultural Conditions:
    Light:
    Full sun (6 or more hours of direct sunlight a day)
    Partial Shade (Direct sunlight only part of the day, 2-6 hours)
    Soil Texture:
    Loam (Silt)
    Sand
    Shallow Rocky
    Soil Drainage:
    Good Drainage
    Moist
    Occasionally Dry
  • Fruit:
    Fruit Type:
    Capsule
    Fruit Description:
    Egg-shaped capsule with 1 seed
  • Flowers:
    Flower Inflorescence:
    Insignificant
    Flower Bloom Time:
    Spring
    Flower Shape:
    Star
    Flower Petals:
    Colored Sepals
    Flower Size:
    < 1 inch
    Flower Description:
    1/8 inch flowers in dense clusters at the tips of forking branches. The petal-like sepals are green with white edges, 2-10 yellow stamens and somewhat spiny to the touch.
  • Leaves:
    Leaf Color:
    Green
    Leaf Type:
    Simple
    Leaf Arrangement:
    Opposite
    Leaf Shape:
    Linear
    Leaf Margin:
    Entire
    Hairs Present:
    No
    Leaf Length:
    < 1 inch
    Leaf Width:
    < 1 inch
    Leaf Description:
    Up to 1 inch long opposite linear to slightly curved green leaves with stiff points are fused at the base. They are arranged at right angles to the pair above and below. The dense spacing can make them appear whorled.
  • Stem:
    Stem Color:
    Green
    Stem Is Aromatic:
    No
    Stem Surface:
    Smooth (glabrous)
    Stem Description:
    Stems have many branches and are spreading to ascending. They are hairless to minutely hairy.
  • Landscape:
    Landscape Location:
    Lawn
    Problems:
    Weedy