The grass in my yard is whatever my neighbors half a mile in all directions have seeded their lawns with. There must be twenty varities. They all grow very quickly for a few days and then stop. If there is a way to program grass growth so some is always in this rapid growth phase there could be a never-ending supply of biomass. That stuff is over and done in a week.
It’s not just growth but the right stuff to turn into ethanol........If it was just growth, kudzu would be perfect........