[7][8] It is also present as an introduced and invasive species in North America, where it was first noted in the Great Lakes region in 1843 and has now spread through most of the continent.

[9][2][10] Persicaria maculosa is an annual herb up to 1 metre (3 ft 3 in) tall,[11] with an erect, rather floppy stem with swollen joints.

The leaf blades often have a brown or black spot in the centre and are narrowly ovate and have entire margins.

Each leaf base has stipules which are fused into a stem-enclosing sheath that is loose and fringed with long hairs at the upper end.

[16] For this reason the transfer of the species to Persicaria by John Kunkel Small in 1903, which used the tautonym, is invalid.

It has been introduced to North America and is naturalised throughout the mainland continent,[18] growing along roadsides, riverbanks, and on fallow ground.