Pennsylvania Smartweed (Polygonum pensylvanicum) is a native annual herb that is often underrated because it is very common. Similarly, the flowers are viewed as small and unattractive. As is often the case this is not correct. While Pennsylvania Smartweed flowers vary in color from white to light pink or bright pink, the bright pink is a vibrant and very attractive flower as can be seen in the photograph on the left.
Growing between 1 and 4 feet tall Pennsylvania Smartweed is a fairly erect plant although it may bend towards light in partial shade. Its stems round, smooth stems vary in color from a light green to faintly red. The leaves are green to dark green in color and may grow to 7 inches in length and 3 inches wide. At the base of the petioles you will find bristle-less sheaths that wrap around the stem.
Some of the upper stems terminate in short spike-like inflorescence that appear like a narrow cylinder and measure 2-3 inches in length. These are densely crowded with small buds and flowers around 1/8 of an inch across. These petite flowers don’t open widely even when in full bloom and have no noticeable floral scent.
Pennsylvania smartweed is found pretty much throughout the US and most commonly occurs on freshwater mudflats to moderately brackish areas including the margins of ponds, lakes, marshes, and similar moist areas.
Seed can be broadcast on top of wet ground, in mudflats or drawdown areas after the last killing frost in the spring. It may also be seeded later to ensure that seed maturity coincides with the arrival of migratory birds. The shiny, black flattened somewhat circular seeds are generally broadcast at a rate of 10-15 pounds per acre.
The nectar of the flower attracts many different insect species including long and short-tongued bees, small butterflies and moths. In addition it is an excellent food for waterfowl including ducks, geese, doves, and other game and non-game species. Furthermore, the dense foliage provides excellent cover for immature waterfowl, marsh birds, and wintering pheasants.