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Milkwort Knotweed
Polygonum polygaloides
About Milkwort Knotweed (Polygonum polygaloides) 0 Nurseries Carry This Plant 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. Polygonum polygaloides is an annual herb producing slender, wiry green stems 1 to 30 centimeters (0. 4-12 inches) in length. The linear or lance-shaped leaves are alternately arranged uniformly along the stem, the ones near the tips of stem branches highly reduced. The leaves have membranous stipules which fuse to form silvery ochrea at the leaf bases. The flowers are mainly located in clusters around the stem tips. They are white, pink, or red, and most remain closed. Subspecies. Some sources accept the following as subspecies of Polygonum polygaloides, while others regard all but subsp. polygaloides as belonging to a distinct species, P. kelloggii. Polygonum polygaloides subsp. confertiflorum (Nutt. ex Piper) J. C. Hickman - from British Columbia east to Saskatchewan and south as far as New MexicoPolygonum polygaloides subsp. esotericum (L. C. Wheeler) J. C. Hickman - California, OregonPolygonum polygaloides subsp. kelloggii (Greene) J. C. Hickman - from British Columbia to ArizonaPolygonum polygaloides subsp. polygaloides - Washington, Oregon, Idaho, Alberta, Montana, Wyoming
Plant Description
Plant Type
Plant Type
Annual herb

0.36 - 11.8 in tall

Flower Color
Flower Color
Pink, White, Red

Wildlife Supported

Butterflies & moths hosted ( 26 likely * ) SHOW ALL

Landscaping Information
Natural Setting
Annual Precipitation: 9.5" - 151.6", Summer Precipitation: 0.51" - 5.67", Coldest Month: 20.1" - 49.4", Hottest Month: 40.1" - 74.4", Humidity: 0.42" - 21.93", Elevation: 122" - 12063"

Alternative Names
Common Names: Polygala Knotweed

Sources include: Wikipedia. All text shown in the "About" section of these pages is available under the Creative Commons Attribution-ShareAlike License. Plant observation data provided by the participants of the California Consortia of Herbaria, Sunset information provided by Jepson Flora Project. Propogation from seed information provided by the Santa Barbara Botanical Garden from "Seed Propagation of Native California Plants" by Dara E. Emery. Sources of plant photos include CalPhotos, Wikimedia Commons, and independent plant photographers who have agreed to share their images with Calscape. Other general sources of information include Calflora, CNPS Manual of Vegetation Online, Jepson Flora Project, Las Pilitas, Theodore Payne, Tree of Life, The Xerces Society, and information provided by CNPS volunteer editors, with special thanks to Don Rideout. Climate data used in creation of plant range maps is from PRISM Climate Group, Oregon State University, using 30 year (1981-2010) annual "normals" at an 800 meter spatial resolution.

Links:   Jepson eFlora Taxon Page  CalPhotos  Wikipedia  Calflora

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