Polygonum aviculare, commonly known as common knotgrass, is an annual herb that originates from a wide range of habitats including roadsides, fields, and waste places in Eurasia. It has since naturalized in temperate regions worldwide. This plant typically grows 4-16 inches high and features semi-erect stems, hairless leaves, and small, inconspicuous white or pink flowers that bloom from June to October. The flowers are not particularly showy, but they do produce a prolific number of seeds.

Common knotgrass is known for its resilience and ability to thrive in compacted soils, which makes it a frequent colonizer of disturbed sites. It is often considered a weed in agricultural and garden settings due to its invasive nature and rapid growth. In cultivation, it prefers full sun to part shade and can tolerate a wide range of soil types with varying drainage. While it is not typically grown for ornamental purposes, it has been used in traditional medicine and can serve as a ground cover in areas where other plants might struggle to survive. Gardeners should be cautious, as it can become invasive outside its native range, and its hardiness allows it to outcompete other plants.CC BY-SA 4.0