"Perennial grasses" refer to types of grasses that live for more than two years. They are plants that come back and regrow each year, as opposed to annual grasses which only live for one year. Full definition
Switchgrass and prairie cordgrass, both native perennial grasses grown for biomass, come out of dormancy when the soil warms up for a week or more, usually in April. (sciencedaily.com)
Faster - growing root systems could allow new plants to take hold more quickly, including perennial grasses like switchgrass and Miscanthus, which are considered viable feedstocks for next - generation biofuel. (scientificamerican.com)
North Carolina Researchers Investigate Potential Ethanol Feedstock Ethanol Produced from Perennial Grass Could Offset 20 % of Gas Use with 9.3 % of Cropland (treehugger.com)