Pennsylvania Smartweed

Persicaria pensylvanica (Polygonum pensylvanicum)

USDA, NRCS. 2018. The PLANTS Database (http://plants.usda.gov, 28 March 2018). National Plant Data Team, Greensboro, NC 27401-4901 USA.
Illustration: USDA-NRCS PLANTS Database / USDA NRCS. Wetland flora: Field office illustrated guide to plant species. USDA Natural Resources Conservation Service.

What is Pennsylvania Smartweed?

Physical Characteristics

Leaves:

• 1.5-8.7 inches long
• 0.39-2 inches wide
• Sword-shaped
• Short leaf stalks

Flowers:

• Rose to white in color
• 0.13-0.16 inches long
• 8 or less stamen
• 8 lobes

Spikes:

• 0.78-1.5 inches long
• Straight

Fruit:

• Round
• Bulging on both sides
• Rough texture
• Dark brown or black in color
• Shiny
• 0.09-0.11 inches long

Stem:

• Branching
• 1-6.5 inches tall
• Greenish or reddish in color

Where Does it Grow?

Pennsylvania smartweed can be found in low marshy ground, mud along irrigation ditches, streams, rivers and pools.

Pros and Cons of Pennsylvania Smartweed

Smartweed seeds are heavily consumed by ducks, small birds, and small mammals. Submerged portions of all aquatic plants provide habitats for many micro and macro invertebrates. These invertebrates in turn are used as food by fish and other wildlife species (e.g. amphibians, reptiles, ducks, etc). After aquatic plants die, their decomposition by bacteria and fungi provides food (called “detritus”) for many aquatic invertebrates.