Aim: Wild strains of elephant grass, Pennisetum purpureum , occur as invasive weed especially in disturbed freshwater swamps of Bayelsa State, Nigeria. A study was undertaken to assess the productivity and bioenergy potentials of the grass. Study Design: A completely randomized experimental design was used. Place and Duration of Study: Wilberforce Island, Bayelsa State, Nigeria and January‐ May 2012. Methodology: Triplicate samples of the wild elephant grass were randomly collected at ten different locations from Wilberforce Island, Bayelsa State. Liquid extract were recovered from the grass, while the resulting bagasse was dried. Results: The grass was found to have a biomass productivity of 7-11t/ha. The liquid extract was analyzed and was found to have the following characteristics; pH (5.55‐5.98), electrical conductivity (14,610-48,214 µS/cm), specific gravity (1.56‐1.60), sugars (2.59‐ 4.47%), and ethanol (1.36‐2.85%), while the gross calorific heating value of the bagasse ranged from 15.76‐17.07 MJ/kg. Conclusion: With these properties, the liquid extracts of elephant grass could be used as