22 April 2021
Persicaria maculosa (syn. Polygonum persicaria) is an annual plant in the buckwheat family, Polygonaceae. Common names include lady’s thumb, spotted lady’s thumb, Jesusplant, and redshank. It is widespread across Eurasia from Iceland south to Portugal and east to Japan. 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
Native to Europe and Asia, where it can be mistaken for Polygonum minus. The latter has narrower leaves, usually less than 1 cm wide. It has been introduced to North America and is naturalised throughout the mainland continent, growing along roadsides, riverbanks, and on fallow ground. In the United States, it is very similar to Pennsylvania smartweed, but redshank has a fringe of hairs at the top of the ochrea, something which Pennsylvania smartweed lacks. The species has also been found in New Zealand and Australia.