This study investigates the seasonal growth patterns of giant reed (Arundo donax L.) in Alabama, aiming to fill the gap in knowledge regarding its growth in the U.S. The research found that growth rates peaked around 66 days after regrowth initiation, with maximum plant height of 5.28 m and biomass yield of 48.56 mg ha-1, demonstrating giant reed's potential as a cellulosic energy crop. Findings indicate the applicability of a Gompertz function to model growth changes over time, supporting improved management practices for this species.