Reed canarygrass (Phalaris arundinacea L.) is a potential biomass crop for energy production but little is known on its optimum management in the northern areas of North America. We determined the effect of three harvest dates (late July, early September, and mid-October) in a one-cut system and four N fertilization (0, 40, 80, and 160 kg N ha^-1) on crop biomass and silage characteristics of reed canarygrass seeded in 2007, and harvested and ensiled in 2008 and 2009 following spring N applications. Delaying harvest from late July to mid-October decreased crop biomass dry matter (DM) yield (-0.8 Mg DM ha^-1), in vitro true digestibility of DM (IVTD; -79 g kg^-1 DM), in vitro neutral detergent fiber (NDF) digestibility (NDFD; -126 g kg^-1 NDF), and K concentration (-7.4 g kg^-1 DM), while it increased soluble carbohydrate ( 14.7 g kg^-1 DM) and ash ( 8.5 g kg^-1 DM) concentrations. Increasing N fertilization from 0 to 160 kg N ha^-1 increased crop biomass DM yield ( 4.3 Mg DM ha^-1), crop biomass NDF ( 29 g kg^-1 DM) and ADF ( 32 g kg^-1 DM) concentrations, decreased IVTD (-65 g kg^-1 DM) and NDFD (-76 g kg^-1 NDF), and did not affect ash concentration. Silage pH and concentrations of lactate and NH₃-N indicated adequate fermentation irrespective of harvest date and N fertilization.