a hydraulically operated gang mower trailer which is connectable to a tractor having a source of pressurized hydraulic fluid for actuating cylinders to raise and lower the mowers . the trailer has a tow bar assembly which permits connection to tractors at varying vertical heights . the trailer has a frame and reel mounting which minimizes the weight carried by the tractor . a stacked set of lever operated hydraulic spool valves which control the flow of pressurized hydraulic fluid to the hydraulic cylinders for lifting and lowering the mowers can be easily moved from tractor to the trailer by disconnecting a minimum number of hydraulic hoses .