Common Knotweed (Note: This is a broadleaf weed, not a true grass species)
Polygonum aviculare · Summer annual; C3 photosynthetic pathway (Broadleaf)
Grass Family
Polygonaceae (Buckwheat family); Tribe: Polygoneae
Grass Category
Invasive/Weed; often found in Turfgrass, Sports Fields, and compacted areas
Variety / Cultivar
None specified; wild-type common knotweed
Hardiness Zones
USDA Zones 3-10; germinates in early spring as soil thaws and thrives in summer heat.
About This Grass
Low-growing, prostrate annual weed forming dense, circular mats. Stems are thin, wiry, and branched. It produces tiny, inconspicuous white-to-pink flowers in leaf axils. Color is typically a dull, bluish-green.
Blade Characteristics
Leaves are alternate, oblong to linear-lanceolate, 1/2 to 1 inch long. They are not true grass blades. Features a papery sheath called an ocrea at each stem node. Color is dull green with smooth margins.
Root System
Deep, thin taproot that can penetrate compacted soils. Does not produce rhizomes or stolons but stems can appear stoloniferous as they lay flat on the ground.
Growing Information
Origin Region
Native to Europe, Eurasia, and North America; widely naturalized globally in temperate climates
Growth Habit
Prostrate, mat-forming, and spreading; grows from a central taproot with wire-like stems
Sunlight & Water Needs
Full sun to partial shade; highly drought tolerant. Thrives in dry, severely compacted soils where turfgrass fails.
Mowing & Maintenance
Extremely low-growing; often survives below the height of regular lawn mowing (0.5 to 2 inches). Maintenance involves herbicide control or mechanical aeration to reduce soil compaction.
Special Characteristics
Exceptional tolerance to foot and vehicle traffic; highly salt-tolerant; indicates high soil compaction and poor aeration.
Ecological Information
Introduced/Naturalized; provide seeds for some bird species but generally considered a nuisance in lawns and manicured landscapes due to its ability to outcompete desired grasses in high-traffic areas.