Carefully position mid sized tractor (18-30 hp) so that Right rear wheel is parked directly on top of rhubarb
(turf tires work best, industrial tread may require repeat process, cleated will damage yard but allow better root blend).
Set PTOs to Neutral, Rear trans to High.
Engage clutch and split rear brake. Disengage diff lock if your tractor is so equipped.
Advance throttle to 1800rpm
While depressing LH brake pedal, abruptly release clutch allowing disengaged wheel to spin free.
Rhubarb will be instantly reduce to the consistancy of grease.
Allow to dry then mow over to blend in with trimmings.
Repeat process if you miss one. Process is identicle for burdock, poke berry, paradise tree, and giant thistle.