Polygonum is a genus of about 130 species of flowering plants in the buckwheat and knotweed family Polygonaceae. Common names include knotweed and knotgrass. In the Middle English glossary of herbs Alphita, it was known as ars-smerte. There have been various opinions about how broadly the genus should be defined. For example, buckwheat has sometimes been included in the genus as Polygonum fagopyrum. Former genera such as Polygonella have been subsumed into Polygonum; other genera have been split off.
Fallopia is a genus of about 12 species of flowering plants in the buckwheat family, often included in a wider treatment of the related genus Polygonum in the past, and previously including Reynoutria. The genus is native to temperate and subtropical regions of the Northern Hemisphere, but species have been introduced elsewhere. The genus includes species forming vines and shrubs.
Polygonum arenastrum, commonly known as equal-leaved knotgrass, is a summer annual flowering plant in the knotweed family Polygonaceae. Other common names include common knotweed, prostrate knotweed, mat grass, oval-leaf knotweed, stone grass, wiregrass, and door weed, as well as many others. It is native to Europe and can be found on other continents as an introduced species and a common noxious weed. Knotweed was first seen in North America in 1809 and is now seen across much of the United States and Canada.
Common knotweed is a common name for several plants and may refer to:
Reynoutria multiflora is a species of flowering plant in the buckwheat family Polygonaceae native to central and southern China. It is known by the English common names tuber fleeceflower and Chinese (climbing) knotweed. It is known as he shou wu in China and East Asia. Another name for the species is fo-ti, which is a misnomer.
Polygonum erectum, commonly called erect knotweed, is a North American species of herbaceous plant in the buckwheat family (Polygonaceae). It is found primarily in the northeastern and north-central parts of the United States, but with scattered populations in other parts of the US and also in Canada.
Persicaria capitata, the pink-headed persicaria, pinkhead smartweed, pink knotweed, Japanese knotweed, or pink bubble persicaria, is an Asian species of plants in the genus Persicaria within the buckwheat family. It is native to Asia and grown as an ornamental in other countries. It has become naturalized in Australia, South Africa and a few scattered locations in the Americas.
Persicaria cespitosa, known as tufted knotweed, is a summer annual weedy plant of the family Polygonaceae, native to eastern Asia, from China to Japan and Southeast Asia, and introduced into North America. The plant grows to 3.5 feet (105 cm) in height with elliptic to lanceolate leaves, usually 20–75 mm long. It has small pink or red flowers arranged in tight terminal spikes.
Fallopia baldschuanica is an Asian species of flowering plant in the knotweed family known by several common names, including Russian-vine, Bukhara fleeceflower, Chinese fleecevine, mile-a-minute and silver lace vine. It is native to Asia, and is growing wild in parts of Europe and North and Central America as an introduced species.
Polygonum douglasii is a species of flowering plant in the knotweed family known by the common name Douglas's knotweed. It is native to much of northern and western North America, where it can be found in many types of habitat, including disturbed areas. It has been found in Canada from British Columbia north to Yukon and east as far as Québec, and in the United States as far south as California, New Mexico, Iowa, and New York.
Polygonum paronychia is a species of flowering plant in the knotweed family known by the common names dune knotweed, black knotweed, and beach knotweed. It is native to the coastline of western North America from British Columbia to California, where it grows in sandy coastal habitat such as beaches, dunes, and scrub.
Persicaria punctata is a species of flowering plant in the knotweed family known by the common names dotted smartweed and dotted knotweed.
Polygonum hickmanii is a rare species of flowering plant in the buckwheat family known by the common names Scotts Valley polygonum and Hickman's knotweed. It is endemic to Santa Cruz County, California, where it is known from only two sites in the Scotts Valley. It grows on coastal prairie on mudstone and sandstone substrates, in an area known for its spring wildflowers. The small plant was first noted in 1990 and described as a new species in 1995. The plant is a federally listed endangered species.
Bistorta macrophylla is a flowering plant species in the buckwheat family Polygonaceae. It is native to mountain regions of West and South China, Bhutan, Nepal, northern India, and Pakistan.
Polygonum striatulum, the striped knotweed or Texas knotweed, is endemic to the U.S. state of Texas but cultivated as an ornamental elsewhere. It occurs there in sterile prairies, granitic soils, and in places that are seasonally moist, at elevations of 100–700 m (330–2,300 ft).
Koenigia polystachya is a species of flowering plant in the knotweed family, known by the common names Himalayan knotweed and cultivated knotweed. It has several regularly used synonyms, including Polygonum polystachyum, Aconogonon polystachyum and Persicaria wallichii.
Polygonum achoreum, common names Blake's knotweed, leathery knotweed or striate knotweed, is a North American species of plants in the buckwheat family. It is widespread across much of Canada and the northern United States.
Polygonum argyrocoleon, with common names silver-sheath knotweed and Persian knotweed, is an Asian species of plants in the buckwheat family. It is native to Siberia, western China, Central Asia, and the Middle East. It has also become naturalized in parts of the United States, primarily the Southwest, and northwestern Mexico.
Polygonum glaucum, common names seabeach knotweed and seaside knotweed, is a North American species of plant in the buckwheat family. It grows on the Atlantic Coast of the United States, from Alabama to Massachusetts, including in salt-water inlets such as Chesapeake Bay and the Hudson River.
