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.
Erysimum menziesii is a species of Erysimum known by the common name Menzies' wallflower.
Lathyrus littoralis is a species of wild pea known by the common name silky beach pea. It is native to the coastline of western North America from British Columbia to California. It is a resident of beaches and dunes.
Polygonum bidwelliae is an uncommon species of flowering plant in the knotweed family known by the common name Bidwell's knotweed. The plant was named for American suffragist Annie Bidwell, who at one time lived in the Bidwell Mansion in Chico, California. She is the person who collected the type specimen in Northern California.
Polygonum bolanderi is an uncommon California species of flowering plant in the buckwheat family known by the common name Bolander's knotweed.
Polygonum californicum is a species of flowering plant in the buckwheat family known by the common name California knotweed. It is native to the west coast of the United States from Washington, Oregon, and northern and central California in the Coast Ranges and Sierra Nevada foothills as far south as Napa and Tulare Counties. It can be found in many types of open habitats.
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 marinense is a rare North American species of flowering plants in the buckwheat family known by the common name Marin knotweed. It is endemic to California, where it is known from just a few locations north and east of San Francisco Bay.
Polygonum minimum is a species of flowering plant in the knotweed family known by the common name broadleaf knotweed. It is native to much of western North America where it can be found in mountainous regions. It grows in the subalpine and alpine climates of high mountain ranges from Alaska to Arizona and New Mexico.
Polygonum parryi is a species of flowering plant in the knotweed family known by the common names Parry's knotweed and prickly knotweed. It is native to the western United States from Washington to California, where it grows in several types of moist, open habitat in mountainous and coastal areas.
Polygonum polygaloides is a North American species of flowering plants in the buckwheat family known by the common names milkwort knotweed and polygala knotweed. It is native to much of western North America, where it can be found in many types of moist habitat. It is a variable species, usually divided into a number of subspecies.
Persicaria punctata is a species of flowering plant in the knotweed family known by the common names dotted smartweed and dotted knotweed.
Polygonum shastense is a species of flowering plant in the knotweed family known by the common name Shasta knotweed. It is native to sections of southwestern Oregon, northwestern Nevada, and northern and central California, where it grows in rocky and gravelly mountainous habitat up to 3300 meters (11,000 feet) elevation. It is most common in the Sierra Nevada. The species name refers to its occurrence on Mount Shasta in Shasta County, California.
Bistorta bistortoides is a perennial herb in the buckwheat and knotweed family Polygonaceae. The species name remains unresolved.
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.
Persicaria longiseta is a species of flowering plant in the knotweed family known by the common names Oriental lady's thumb, bristly lady's thumb, Asiatic smartweed, long-bristled smartweed, low smartweed, Asiatic waterpepper, bristled knotweed, bunchy knotweed, and tufted knotweed. It is native to Asia, and it is present in North America and Europe as an introduced species and often a weed.
Koenigia davisiae is a flowering plant in the knotweed family that is known by the common names Davis' knotweed or Newberry knotweed.
Koenigia phytolaccifolia is a species of flowering plant in the knotweed family, known by the common name poke knotweed.
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 majus is a North American species of flowering plant in the buckwheat family known by the common name wiry knotweed. It grows in the western United States and western Canada, from British Columbia south as far as the Sierra Nevada of northwestern Inyo County in California, east as far as Montana. Knotweed is a spreading, wiry annual weed that rarely grows higher than a few inches. The leaves are tiny, oblong, bluish-green, and 14 inches broad and 1 inch long. The flowers are tiny and unobtrusive, whitish-green in colour, and appear in the leaf axils in the fall. Knotweed may grow into a dense mat with a diameter of up to three feet, strangling out ideal grass and plants. The branches of this evergreen plant form a strong, wiry mat that reaches barely a few centimeters above the earth. They appear constantly, and gardeners are always fighting them. We cultivate the soil by tilling and enriching it. We plant our flowers and veggies, but the weeds make the most of our efforts. We believe we've got situation under control, but then we walk around to discover different things growing where we didn't expect it: knotweed sprawls down our walkways and up between our patio's paving stones.
