Scientific NamePolygonum lapathifolium
Other Common Names:
Synonyms (former Scientific Names):
This erect summer annual can grow from 3 to 5 feet tall, and can be found flowering from June through October.
The leaves are generally lance shaped with smooth margins. The whitish undersides have minute sunken glands, while the upper surface remains smooth. Stems are connected to the stalk by thick sheaths.
Pale smartweed is very similar to Lady's Thumb, but can be distinguished by the hair on the lower surfaces of its leaves, and by the lack of hairs on the upper edge of the leaf sheaths.
Flower Seed Head
The white to pale pink flowers can be found on 1 to 3 inch long stalks in dense, hanging spikes. Each 5-petaled flower never opens, and is insect or self pollinated.
The seeds develop in an ovate, flattened achene that is slightly concave on either side. Each achene can grow up to 2 mm in length. The individual seeds are shiny, lens shaped, and black.
Pale smartweed prefers loose, rich, acidic soils high in organic matter. It can be found in wet environments such as areas near ponds, streams, wet fields, and waste places.
upright and nonwoody
Thorns or Spines
Approximate Flower Diameter
Dominant Flower Color
shorter than leaf
Stem Cross Section
round or oval