Calamovilfa arcuata
Common Name: Cumberland reed grass 
Type: Ornamental grass
Family: Poaceae
Native Range: Central United States
Zone: 6 to 8
Height: 3.00 to 4.00 feet
Spread: 3.00 to 4.00 feet
Bloom Time: August to September
Bloom Description: Green
Sun: Full sun
Water: Medium to wet
Maintenance: Medium
Suggested Use: Rain Garden
Flower: Insignificant
Tolerate: Wet Soil

Culture

Best grown in moist to wet soils in full sun. Tolerates part shade but begins to lose its form in too much shade, growing more openly and falling over. In the wild, plants typically root in sandy alluvium between rocks along small rivers and streams. Grows in clumps which may spread by rooting at the nodes. Clumps may be cut back to the ground in late winter to early spring.

Noteworthy Characteristics

Calamovilfa arcuata, commonly known as Cumberland reed grass, is a riverine sandgrass whose growth in the wild is limited to a few scattered populations found in sunny locations along flood-scoured exposures of bedrock, cobble and gravel along streams or small rivers located in the Cumberland Plateau area of Kentucky, Tennessee and northern Alabama. Several disjunct populations may also be found in a small area of southeastern Oklahoma and adjacent western Arkansas. Typical habitat is rocky stream/river banks and cobble/gravel bars (sometimes called river scour prairies) which are kept open and maintained by periodic flooding. Flood water will wash over these areas scouring out certain species of plants (including potentially invasive ones) that are simply not adapted to this type of environment. Many grasses, flowering herbs and low shrubs live in these harsh conditions, but larger woody plants and trees are scarce. Cumberland reed grass was first discovered by K. E. Rogers in Cumberland County, Tennessee in 1970. The total number of populations of this rare species today probably does not exceed 60.

Cumberland reed grass typically grows in clumps to 3-4 1/2’ tall. It features short, compact rhizomes, glabrous stems, culm nodes with fine hairs, and leaf blades (each to 12-34” long) with sharp downward pointed teeth. Leaves are clustered near the bottom of the plant. Inflorescence is a panicle with narrow raceme-like or spike-like branches. Flowers bloom in August-September. Cumberland reed grass is similar in appearance to Tridens flavus (purpletop) and Panicum virgatum (switch grass).

Genus name comes from the Greek word kalamos meaning reed and vilfa meaning a genus of grass.

Specific epithet is in reference to the arcuate (curved) florets of this grass.

Problems

No serious insect or disease problems. The survival of this sandgrass in the wild depends in large part on freely flowing unpolluted streams. Construction of reservoirs or dams or alteration of streambanks affecting the water flow or water pollution can significantly alter and in some cases destroy downstream cobble bars and plant communities living thereon. Basically any alteration of the streambanks, sandbars and/or water flow must be avoided.

Garden Uses

May be very difficult to locate this reed grass in commerce. Homeowners may have difficulty locating a good habitat for this plant on residential real estate.