In Ukraine, balancing agricultural efficiency, food security, and energy development is crucial. Energy crops offer a sustainable raw material due to their adaptability and high biomass yields, supporting biofuel production and value-added products like bioplastics and paper. However, the war has severely degraded agricultural land, necessitating reclamation efforts to restore productivity and enhance bioenergy potential. A five-year field study (2019–2023) in Ukraine’s Forest-Steppe and Steppe zones assessed energy crop yields on marginal lands. Research methods included field studies, gravimetric biomass analysis, data visualization, and statistical analysis (ANOVA, LSD at 5% significance). Findings showed that drooping sorghum and perennial sorghum exhibited the highest drought resistance, while switchgrass and drooping sorghum demonstrated the best frost resistance. Drooping sorghum also had the greatest lodging resistance, whereas switchgrass and perennial sorghum were more prone to lodging, particularly in the Forest-Steppe, suggesting a correlation with precipitation levels. The vegetation period varied by region, influenced by plant biology and environmental factors. In the Steppe, it lasted 170.6–192.0 days, with drooping sorghum having the longest cycle. In the Forest-Steppe, it ranged from 170.3 to 181.3 days, with switchgrass exhibiting the longest duration. Biomass yields were higher in the Steppe (7.8–11.2 t/ha) than in the Forest-Steppe (7.4–10.4 t/ha). Over four years, switchgrass and perennial sorghum achieved the highest total biomass yields: 56.0 t/ha and 53.6 t/ha in the Steppe, and 51.9 t/ha and 51.7 t/ha in the Forest-Steppe, respectively. Drooping sorghum produced 46.1 t/ha (Steppe) and 39.9 t/ha (Forest-Steppe), while big bluestem had the lowest yield (39.1 t/ha and 36.9 t/ha). Switchgrass and perennial sorghum proved to be the most productive and adaptable energy crops. Their stable biomass production makes them promising candidates for biofuel manufacturing. Future research will explore strategies to enhance yields, particularly through spring foliar fertilization on marginal lands.