Performance of Warm Season Grasses in Riparian Zones.

Native warm season grasses are a potentially important component of riparian buffers.  There is a need to determine the suitability of selected warm season grass species for use in riparian buffers where occasional flooding can occur.  In a previous greenhouse pot experiment, potential candidates of warm season grasses were identified for their ability to extend their roots into saturated soil.  To verify the results, this study was conducted in actual field locations in New York, Pennsylvania and Maryland with high soil water tables or periodic flooding.  Nine warm season grass cultivars of the following species were included in this study: big bluestem, switchgrass, indiangrass, prairie cordgrass, and eastern gamagrass.  Each plot consisted of three rows planted on 30 cm centers of individual plants started in the greenhouse with the rows perpendicular to the stream bed.  Survival, growth, vegetative vigor and yields were evaluated for three years of the study.  The nine cultivars were averaged across the four locations and ranked. ‘Red River’ prairie cordgrass, ‘Meadowcrest’ eastern gamagrass, ‘Hightide’ switchgrass and ‘Shelter’ switchgrass consistently performed the best for survival, vigor and biomass production.  ‘Suther’ big bluestem and ‘Osage’ indiangrass were intermediate, while ‘Niagara’ big bluestem, ‘Suther’ indiangrass and ‘Bonilla’ big bluestem were consistently the lowest ranked cultivars.  Flooding tolerance determined in the greenhouse study did a reasonably good job in predicting performance under riparian conditions in the field.  However, enough difference existed between the greenhouse and field results to recommend the need to verify results with field studies before recommending cultivars for use in riparian zones.