Assign color based on values to trellis column chart

Hi, I am using trellis column chart in my dashboard. I am looking to change bar colors based on values. Requirement : if value = "-1" it should be Green, All others Red. I am able to change same color for all values but not sure how to do it based on values. ["0x00A572"] ![alt text][1] Thanks [1]: /storage/temp/273535-trellis.png