A flow distributor apparatus (40) for a vertical spreader (24) operable for discharging a flow of straw or other crop residue in a sideward direction over a field, the flow distributor apparatus (40) including a flow guide element (42), an adjusting mechanism (78), and a coupling connector (74) connecting the flow guide element (42) to the adjusting mechanism (78) for controllable repositioning of the flow guide element (42) relative to the impellers (28, 30). The flow guide element (42) is disposed generally adjacent to the back plate (36) of the spreader (24) and intermediate the impellers (28, 30) with an apex portion (44), laterally extending arm portions, and longitudinally extending crop residue flow surfaces, at least portions of which crop residue flow surfaces extend beneath the impellers (28, 30). The adjusting mechanism (78) is operable to effect at least either vertical, horizontal, or rotational movement of the flow guide element (42) relative to the impellers (28, 30) to adjustably vary the clearances between the outer swept diameters of the impellers (28, 30) and the crop residue flow surfaces to control the sidewardly outwardly discharge of crop residue from the spreader (24).
