Ask Mr. Smarty Plants

From an excellent previous answer on this subject from Mr. Smarty Plants:

We recommend grasses for controlling erosion because of their extensive fibrous root systems that serve to hold the soil in place.  However, just throwing grass seeds over the side of your bank is not going to work very well.  The seeds need moisture to germinate.  If the moisture comes in the form of rain, it is likely to wash the seeds down the bank into the river before that have a chance to germinate and take root.  There are two possible solutions—an erosion control blanket or pneumatic compost/seed application.  The erosion-control fabric works by slowing the runoff water and allowing sediments to fall out rather than be washed away. Seeds are sown under the erosion-control material and grow up through the matting when they germinate. You can also insert plants into the soil by cutting through the matting. The roots of the plants that are growing through the erosion-control material anchor the soil to stop the erosion. If you use erosion-control blankets made of biodegrable material, they will eventually disappear leaving the plants to control the problem.  Many nurseries carry this erosion control fabric. 

The compost/seed application may be a bit more complicated and expensive than you had in mind since it does require a pneumatic blower, or some mechanical means, to spread the compost/seed mix. The US Composting Council offers information about suppliers of compost and compost technology, but I don't really know if this could be a do-it-yourself project.  You might check with a landscaping or environmental consulting company in your area who might have the machinery to do this to learn about the feasability and expense of applying the compost/seed mixture this way. You can find the names of Landscape Professionals and Environmental Consultants in your area that specialize in native plants by searching in our National Suppliers Directory.

Here are some grasses that should work on your bank.  However, since we don't know the specifics of how much sun/shade or the exact soil type you have there, you will need to compare those aspects of your site with the GROWING CONDITIONS given for each grass. We also selected some low-growing shrubs that might give you some coverage. 

Grasses native to Kentucky for erosion control

Andropogon gerardii (big bluestem) - 4 to 8 ft. tall, medium water use, sun or part shade

Bouteloua curtipendula (sideoats grama) - 2 to 3 ft. tall, perennial, warm season grass, medium water use, sun or part shade

Carex blanda (eastern woodland sedge) - 1 to 3 ft. tall, perennial, sun, part shade or shade

Carex texensis (Texas sedge) - to 1 ft. tall, perennial, medium water use, sun or part shade

Chasmanthium latifolium (Inland sea oats) -2 to 4 ft. tall, perennial, deciduous, med. water use, part shade or shade

Deschampsia cespitosa (tufted hairgrass) - 2 to 3 ft. tall, cool-season perennial, semi-evergreen, low water use, part shade

Muhlenbergia schreberi (nimblewill) - 1 to 2 ft. tall, perennial, moist soil, part shade or shade

Schizachyrium scoparium (little bluestem) - 3 to 6 ft. tall, perennial, low water use, sun or part shade

Shrubs native to Kentucky for erosion control

Comptonia peregrina (sweet fern) - 2 to 4 ft. tall, perennial, low water use, part shade

Hypericum prolificum (shrubby St. Johnswort) - to 3 ft. tall, perennial, deciduous, blooms yellow June to August, part shade or shade

Symphoricarpos orbiculatus (coralberry) - 4 ft. tall, deciduous, blooms white, green April to July, medium water use, part shade or shade

Pictures of Kentucky native plants for erosion from our Native Plants Image Gallery:

Andropogon gerardii

Bouteloua curtipendula

Carex blanda

Carex texensis

Chasmanthium latifolium

Deschampsia cespitosa

Muhlenbergia schreberi

Schizachyrium scoparium

Comptonia peregrina

Hypericum prolificum

Symphoricarpos orbiculatus