• Photo of Scleranthus annuus (Scleranthus annuuss)

Plant Profile: Scleranthus annuus

Taxonomy: Scleranthus annuus

Names

Annual Knawel, German Knotweed, German Moss

  • Photo of Scleranthus annuus (Scleranthus annuuss)

Phonetic Spelling:

Genus:Scleranthus

Species:annuus

Family:Caryophyllaceae

Knawel, a winter annual weed belonging to the pink family, originates from Eurasia and Africa but has spread to many regions across the United States and Canada. This diminutive plant typically reaches heights of 2 to 5 inches, with its sprawling and upright stems capable of creating dense mats. It germinates during the winter months, thrives in warmer spells, flowers in early spring, and ultimately dies off by late spring or early summer, primarily reproducing through seeds.

This weed is adaptable to various environments and is commonly found in disturbed areas, fields, and lawns. It favors sandy and gravelly soils, demonstrating drought resistance while also being able to thrive in moist conditions and tolerating both full sun and partial shade.

Scleranthus annuus Feature Summary

Scleranthus annuus Image Gallery

Tags

#full sun tolerant
#drought tolerant
#weed
#weedy
#winter annual weed
#cool season weed
#lawn weed
#dry soils tolerant
#partial shade tolerant

Similar Plants

Scleranthus annuus is often confused with:

Scleranthus annuus Feature Summary

Attributes
Has been used in herbal medicine
Macaronesia, Europe, Asia, North Africa
Eastern, Central and Pacific coast of USA and Canada
Fruit
Egg-shaped capsule with 1 seed
Flowers
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.
Colored Sepals
< 1 inch
Leaves
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.
< 1 inch
< 1 inch
Stem
Stems have many branches and are spreading to ascending. They are hairless to minutely hairy.
Smooth (glabrous)
Whole Plant Traits
Spreading
Horizontal
Creeping
Prostrate
Cultural Conditions
Full sun (6 or more hours of direct sunlight a day)
Partial Shade (Direct sunlight only part of the day, 2-6 hours)
Good Drainage
Moist
Occasionally Dry
Loam (Silt)
Sand
Shallow Rocky

Scleranthus annuus Attributes

Scleranthus annuus: Uses (Ethnobotany)

Has been used in herbal medicine

Scleranthus annuus: Country Or Region Of Origin

Macaronesia, Europe, Asia, North Africa

Scleranthus annuus: Distribution

Eastern, Central and Pacific coast of USA and Canada

Scleranthus annuus: Life Cycle

Annual
Biennial
Bulb
Perennial
Woody

Scleranthus annuus Fruit

Scleranthus annuus: Fruit Description

Egg-shaped capsule with 1 seed

Scleranthus annuus: Fruit Type

Achene
Aggregate
Berry
Capsule
Caryopsis
Drupe
Follicle
Legume
Nut
Pome
Samara
Schizocarp
Siliqua

Scleranthus annuus Flowers

Scleranthus annuus: 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.

Scleranthus annuus: Flower Inflorescence

Catkin
Corymb
Cyme
Head
Insignificant
Panicle
Raceme
Solitary
Spadix
Spike
Umbel

Scleranthus annuus: Flower Bloom Time

Winter
Spring
Summer
Fall

Scleranthus annuus: Flower Petals

2-3 rays/petals
4-5 petals/rays
6 petals/rays
7 - 20 petals/rays
asymmetrical petals
Bracts
Colored Sepals
fused petals
more than 20 petals/rays
Tepals

Scleranthus annuus: Flower Shape

Bell
Cross
Crown
Cup
Dome
Funnel
Irregular
Lipped
Radial
Saucer
Star
Trumpet
Tubular
Urn
Wheel

Scleranthus annuus: Flower Size

1-3 inches
3-6 inches
< 1 inch
> 6 inches

Scleranthus annuus Leaves

Scleranthus annuus: 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.

Scleranthus annuus: Leaf Color

spa
Green

Scleranthus annuus: Leaf Type

Compound (Pinnately , Bipinnately, Palmately)
Fronds
Needles
Sheath
Simple

Scleranthus annuus: Leaf Arrangement

Alternate
Opposite
Other/more complex
Rosulate
Whorled

Scleranthus annuus: Leaf Shape

Acicular
Auriculate
Cordate
Cuneate
Deltoid
Elliptical
Filiform
Lanceolate
Linear
Oblanceolate
Oblong
Obovate
Obtuse
Orbicular
Ovate
Palmasect
Palmatifid
Peltate
Pinnatifid
Pinnatisect
Reniform
Rhomboidal
Spatulate
Subcordate
Subulate

Scleranthus annuus: Leaf Margin

Crenate
Crenulate
Dentate
Denticulate
Doubly Crenate
Doubly Dentate
Doubly Serrate
Entire
Lobed
Serrate
Sinuate
Undulate

Scleranthus annuus: Hairs Present

No
Yes

Scleranthus annuus: Leaf Length

< 1 inch
1-3 inches
3-6 inches
> 6 inches

Scleranthus annuus: Leaf Width

< 1 inch
1-3 inches
3-6 inches
> 6 inches

Scleranthus annuus Stem

Scleranthus annuus: Stem Description

Stems have many branches and are spreading to ascending. They are hairless to minutely hairy.

Scleranthus annuus: Stem Color

grass
Green

Scleranthus annuus: Stem Is Aromatic

No
Yes

Scleranthus annuus: Stem Surface

Corky Ridges
Covered with a powdery bloom (glaucous)
Dull
Hairy (pubescent)
Polished
Smooth (glabrous)

Scleranthus annuus Whole Plant Traits

Scleranthus annuus: Plant Type

Annual
Bulb
Carnivorous
Edible
Epiphyte
Fern
Ground Cover
Herb
Herbaceous Perennial
Houseplant
Mushroom
Native Plant
Ornamental Grasses and Sedges
Perennial
Poisonous
Rose
Shrub
Succulent
Tree
Turfgrass
Vegetable
Vine
Water Plant
Weed
Wildflower

Scleranthus annuus: Habit/Form

Arching
Ascending
Broad
Cascading
Climbing
Clumping
Columnar
Conical
Creeping
Dense
Erect
Horizontal
Irregular
Mounding
Multi-stemmed
Multi-trunked
Open
Oval
Prostrate
Pyramidal
Rounded
Spreading
Vase
Weeping

Scleranthus annuus Cultural Conditions

Scleranthus annuus: Light

Dappled Sunlight (Shade through upper canopy all day)
Deep shade (Less than 2 hours to no direct sunlight)
Full sun (6 or more hours of direct sunlight a day)
Partial Shade (Direct sunlight only part of the day, 2-6 hours)

Scleranthus annuus: Soil Drainage

Frequent Standing Water
Good Drainage
Moist
Occasional Flooding
Occasionally Dry
Occasionally Wet
Very Dry

Scleranthus annuus: Soil Texture

Clay
High Organic Matter
Loam (Silt)
Sand
Shallow Rocky

Scleranthus annuus Landscape

Scleranthus annuus: Landscape Location

Coastal
Container
Hanging Baskets
Houseplants
Lawn
Meadow
Naturalized Area
Near Septic
Patio
Pond
Pool/Hardscape
Recreational Play Area
Riparian
Rock Wall
Slope/Bank
Small Space
Vertical Spaces
Walkways
Woodland

Scleranthus annuus: Problems

Allelopathic
Contact Dermatitis
Frequent Disease Problems
Frequent Insect Problems
Invasive Species
Malodorous
Messy
Poisonous to Humans
Problem for Cats
Problem for Children
Problem for Dogs
Problem for Horses
Short-lived
Spines/Thorns
Weak Wood
Weedy