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Polygonum lapathifolium (Curlytop knotweed)
Loughmiller, Campbell and Lynn

Polygonum lapathifolium

Polygonum lapathifolium L.

Curlytop Knotweed, Curl-top Smartweed, Pale Smartweed

Polygonaceae (Buckwheat Family)

Synonym(s): Persicaria incarnata, Persicaria lapathifolia, Persicaria tomentosa, Polygonum incanum, Polygonum incarnatum, Polygonum lapathifolium ssp. pallidum, Polygonum lapathifolium var. incanum, Polygonum lapathifolium var. nodosum, Polygonum lapathifolium var. ovatum, Polygonum lapathifolium var. prostratum, Polygonum lapathifolium var. salicifolium, Polygonum nodosum, Polygonum oneillii, Polygonum pensylvanicum ssp. oneillii, Polygonum scabrum, Polygonum tomentosum

USDA Symbol: POLA4

USDA Native Status: L48 (N), AK (I), CAN (I), GL (I), SPM (I)

Polygonum lapathifolium has arching, white or pale rose flower spikes and usually smooth stems.


From the Image Gallery

27 photo(s) available in the Image Gallery

Plant Characteristics

Duration: Annual
Habit: Herb
Fruit Type: Achene
Size Notes: Up to about 3 feet tall.

Bloom Information

Bloom Color: White , Pink , Green
Bloom Time: Apr , May , Jun , Jul , Aug , Sep , Oct , Nov


USA: AK , AL , AR , AZ , CA , CO , CT , DC , DE , FL , GA , IA , ID , IL , IN , KS , KY , LA , MA , MD , ME , MI , MN , MO , MS , MT , NC , ND , NE , NH , NJ , NM , NV , NY , OH , OK , OR , PA , RI , SC , SD , TN , TX , UT , VA , VT , WA , WI , WV , WY
Canada: NB , NS , PE

Find Seed or Plants

Find seed sources for this species at the Native Seed Network.

National Wetland Indicator Status

This information is derived from the U.S. Army Corps of Engineers National Wetland Plant List, Version 3.1 (Lichvar, R.W. 2013. The National Wetland Plant List: 2013 wetland ratings. Phytoneuron 2013-49: 1-241). Click here for map of regions.

From the National Organizations Directory

According to the species list provided by Affiliate Organizations, this plant is on display at the following locations:

Native Seed Network - Corvallis, OR


Bibref 328 - Wildflowers of Texas (2003) Ajilvsgi, Geyata.

Search More Titles in Bibliography

Web Reference

Webref 38 - Flora of North America (2019) Missouri Botanical Garden, St. Louis, MO & Harvard University Herbaria, Cambridge, MA.
Webref 23 - Southwest Environmental Information Network (2009) SEINet - Arizona Chapter

Additional resources

USDA: Find Polygonum lapathifolium in USDA Plants
FNA: Find Polygonum lapathifolium in the Flora of North America (if available)
Google: Search Google for Polygonum lapathifolium


Record Modified: 2023-02-23
Research By: TWC Staff

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