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Polygonum pensylvanicum (Pennsylvania smartweed)
Brundage, Stephanie

Polygonum pensylvanicum

Polygonum pensylvanicum L.

Pennsylvania Smartweed, Pink Smartweed

Polygonaceae (Buckwheat Family)

Synonym(s): Persicaria bicornis, Persicaria longistyla, Persicaria mississippiensis, Persicaria pensylvanica, Persicaria pensylvanica var. dura, Polygonum bicorne, Polygonum longistylum, Polygonum longistylum var. omissum, Polygonum mexicanum, Polygonum mississippiense, Polygonum mississippiense var. interius, Polygonum pensylvanicum var. durum, Polygonum pensylvanicum var. eglandulosum, Polygonum pensylvanicum var. genuinum, Polygonum pensylvanicum var. laevigatum, Polygonum pensylvanicum var. rosiflorum

USDA Symbol: pope2

USDA Native Status: L48 (N), AK (N), CAN (N)

Dense, erect, spike-like clusters of small, bright pink flowers are on sticky-haired stalks.

About 75 species of smartweeds occur in North America. They are mainly are identified by their spikes of numerous flowers and encircling leaf sheaths. A closely related species, Pale Smartweed (P. lapathifolium), has white or pale rose, arching flower spikes and usually smooth stems. Both are found in gardens as well as in damp waste places. The seeds of these plants are eaten by songbirds and waterfowl. There are also climbing species of smartweeds.


From the Image Gallery

111 photo(s) available in the Image Gallery

Plant Characteristics

Duration: Annual
Habit: Herb
Fruit Type: Achene
Size Notes: Up to about 6 feet tall.
Leaf: Green

Bloom Information

Bloom Color: White , Red , Pink
Bloom Time: May , Jun , Jul , Aug , Sep , Oct , Nov , Dec


USA: AK , AL , AR , AZ , CA , CO , CT , DC , DE , FL , GA , IA , 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 , VA , VT , WI , WV , WY
Canada: MB , NB , NL , NS , ON , QC
Native Distribution: Throughout East, except Prairie Provinces; also in most of West.
Native Habitat: Moist waste places, fields.

Growing Conditions

Water Use: Medium
Light Requirement: Sun
Soil Moisture: Moist
CaCO3 Tolerance: Medium


Conspicuous Flowers: yes

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:

Fredericksburg Nature Center - Fredericksburg, TX
Native Seed Network - Corvallis, OR

Herbarium Specimen(s)

NPSOT 0847 Collected Apr 29, 1994 in Bexar County by Harry Cliffe
NPSOT 0898 Collected Jun 24, 1994 in Bexar County by Harry Cliffe

2 specimen(s) available in the Digital Herbarium

Wildflower Center Seed Bank

LBJWC-1354 Collected 2014-10-05 in Hays County by Lady Bird Johnson Wildflower Center

1 collection(s) available in the Wildflower Center Seed Bank

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


Record Modified: 2023-05-02
Research By: TWC Staff

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