Scour Bar Wet Meadow (Piedmont-Central Appalachian)

The Scour Bar Wet Meadow is found in and along the Potomac River. Vegetation may be sparse in years of high water. But in a normal growing season, this community consists of a wide variety of wildflowers and other plants that grow 3 to 6 feet tall. (There is more than one type of Scour Bar Wet Meadow; this type is found in the Piedmont and Central Appalachians.) 

This natural community occurs in and along the Potomac River in the Piedmont and mountains of Maryland, Virginia, and West Virginia.

The range map shows the states in which this natural community has been documented.

More About This Natural Community

Scour Bar Herbaceous Vegetation is found on sandbars and sandy riverbanks, which are frequently overrun when the river is running high. During these high-water events, moving water covers the vegetation, reworks the sediment, and even rearranges sandbars and washes away plants.

Plants that grow back from their roots each year are not always successful in this natural community, because if they are washed away, they’re gone for good. Annuals—which reseed each year—have the advantage here. Even if the parent plant is torn from the roots, seeds from the plant may survive and sprout in the spring.

In years of high water, vegetation may be sparse, but during normal years, there is a lush cover of vegetation 3 to 6 feet tall during the growing season. Look for blue mistflower, curlytop knotweed, and eastern black nightshade. There are also many non-native invasive plants, such as sweet wormwood*, Mexican-tea*, and jimsonweed* (* indicates non-native). Seeds of these plants are carried in the river when the water is high, then deposited in the sand when the water level falls.

For a more in-depth look at this community, click on a link under “Where to Explore It.”

Look for It in These National Parks

  • Appalachian Trail (Central Appalachians)
  • Chesapeake and Ohio Canal National Historical Park
  • George Washington Memorial Parkway
  • Harpers Ferry National Historical Park 

Conservation Status

How vulnerable is a natural community? Is it at risk of elimination? Learn about conservation status.

Global Conservation Status: 
GNR – Not yet assessed


Official names reduce confusion by providing a common language for talking about natural communities. Why so many names?

Common Name: 
Scour Bar Wet Meadow (Piedmont-Central Appalachian)
Scientific Name Translated: 
Late-flowering Thoroughwort - (Curlytop Knotweed, Dotted Smartweed, Pennsylvania Smartweed) Riverbar Wet Meadow
Classification Code: