Polygonum erectum, commonly called erect knotweed, is a North American species of herbaceous plant in the buckwheat family (Polygonaceae).

It is tolerant of ecological degradation, and can also be found in disturbed open areas such as pastures and lawns.

[2][3] It was once cultivated for food by Native Americans as part of the group of crops known as the Eastern Agricultural Complex.

[citation needed] Polygonum erectum is an erect annual growing 10–75 cm (4–29.5 in) tall with many to few, non-wiry branches.

The pedicels are shorter or equal the length of the calyx and typically longer than the ocreae.