Rocky Bar and Shore – Water-willow Type

The Rocky Bar and Shore – Water-willow Type grows on shoals or bars of rocky streams and riverbeds. It’s easy to recognize because it features primarily one plant: American water-willow, a flowering plant (not a willow tree!) that grows in colonies, rooted in shallow flowing water. (There is more than one type of Rocky Bar and Shore natural community; this type features Water-willow.)

This is a widespread natural community that is found along rivers from Alabama to New York (and perhaps even in Quebec), and from the Carolinas to Oklahoma. It’s found primarily in the Piedmont, Interior Low Plateau, Cumberland Plateau, Ozarks, Ouachita Mountains, Central Appalachians, and adjacent provinces.

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

More About This Natural Community

The physical setting of this natural community is too challenging for most plants. The rocky bars are typically submerged in shallow running water. During flooding, the shallow running water becomes deep, and vegetation may be completely submerged. During droughts, the bars may be high and dry. American water-willow can survive in all of these situations, and the net-like roots of water-willow colonies hold fast in running water and even floods.

In some cases, water-willow is the only species in this natural community. Lizard’s-tail can be present and even abundant. Other species that may be found in smaller numbers include goldenclub, water knotweed, rice cutgrass, whitegrass, and common threesquare. Tree such as American sycamore, silver maple, and river birch sometimes sprout here, but the seedlings or saplings are typically washed away by floods before they mature.

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)
  • Big South Fork National River & Recreation Area
  • Buffalo National River
  • Chesapeake and Ohio Canal National Historical Park
  • Chickasaw National Recreation Area
  • Delaware Water Gap National Recreation Area
  • Gauley River National Recreation Area
  • George Washington Memorial Parkway
  • Harpers Ferry National Historical Park
  • Little River Canyon National Preserve
  • Mammoth Cave National Park
  • Manassas National Battlefield Park
  • Natchez Trace Parkway
  • New River Gorge National Preserve
  • Obed Wild & Scenic River
  • Stones River National Battlefield
  • Upper Delaware Scenic & Recreational River

Conservation Status

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

Global Conservation Status: 
G4G5 – Apparently Secure to Secure


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

Common Name: 
Rocky Bar and Shore – Water-willow Type
Scientific Name Translated: 
American Water-willow Riverbed Vegetation
Classification Code: