Elephantgrass (Pennisetum purpureum Schum.) and energycane (Saccharum sp.) are being evaluated in the colder subtropics of Florida, USA, as biomass energy crops. At one location near Gainesville, annual dry biomass yields of elephantgrass (full-season growth) in excess of 45 Mg ha-l have been reported. Our objective was to determine if these prolific bunchgrasses could be stored as silage. Three elephantgrasses (two 'tall' and one 'dwarf') and a tall energycane were harvested one, two, and three times per year and ensiled (directcut) during 1986 and 1987. Mean pH values ranged from 3"8 to 4"0 for tall elephantgrass silages made from plants harvested at the different frequencies. Highest pH values were obtained from silages made from immature dwarf elephantgrass plants harvested three times per year (2-year mean was 4.3). Lactic acid was the major end-product offermentation in most silages with the exception of those made from immature dwarf elephantgrass and energycane plants, where lactic and acetic acids were both major fermentation components. Dry matter (DM) recoveries for all silages ranged from 843 to 984 g kg-z of DM ensiled. The ease with which elephantgrass and energycane were preserved as silage was attributed to adequate levels of water-soluble carbohydrates and the inherently low buffering capacities in standing forages.