Ask Mr. Smarty Plants

Generally speaking, plants with fibrous root systems or those that spread using stolons , such as Alnus serrulata (Hazel alder) are the best for holding a bank and resisting erosion.

Although you do not indicate anything about your conditions (light exposure and soild moisture) you can search our Native Plant database for likely candidates using the Combination Search function.  If you select: New York, shrubs, both the 6-12 ft and 12-36 ft sizes and then select your specific conditions, the database will generate a list of plants that occur in your area that meet those criteria.  Each plant on the list is linked to a detailed information page with images that will give you the information you need, even though you cannot sort specifically for "erosion preventing shrubs less than 25 ft in height".  For instance, the entry for the alder calls it "A multiple-trunked, suckering shrub, 12-20 ft. tall, with a picturesque habit and shiny gray-brown bark. Summer foliage is dark green and glossy, becoming yellow, tinged with red, in fall."  It is adapted to all light conditions, so as long as your site is moist enough, it would be a good choice.  Look for terms like "suckering, thicket-forming, or colony-forming" in the descriptions.

Some other plants to consider are:

Amorpha fruticosa (Indigo bush)

Calycanthus floridus (Eastern sweetshrub)

Cornus racemosa (Gray dogwood)

Ilex glabra (Inkberry)

Rhus glabra (Smooth sumac)

Sambucus nigra ssp. canadensis (Common elderberry)

Viburnum lentago (Nannyberry)

By choosing a variety of native plants of differing sizes and forms you will create not just a living wall, but one that is attractive throughout the seasons and offers wildlife habitat, bringing your property to life with songbirds and butterflies.