A grass mower comprising a power generator, a blade reel, a drive drum, and a power split device. The split power device can include a single power input shaft, a reel output shaft, a drum output shaft, and at least one continuously variable transmission hub operably connecting the reel output shaft and/or the drum output shaft to the power input shaft such that torque and rotational speed delivered by the power input shaft is transferrable to the reel and/or drum output shafts at any infinitely variable ratio. The power split device structured and operable to transfer the torque and rotational speed delivered by the power input shaft to both the reel and drum output shafts such that a rotational speed of the blade reel and a rotational speed of the drive drum are both generated from the power delivered by the power input shaft and are both independently controlled.