"restricts snow accumulation" how?  Unless you heat it, it's not gonna melt any faster, which means accumulation.  You seem to be suggesting a zig-zag pattern of toughs/valleys, which (1) I don't see how that would make it melt any faster over a wide area, and (2) even if it did, would be accomplished a helluva lot cheaper with simple materials instead of very expensive solar panels.  (We'd also already be seeing it done if troughs worked to eliminate snow load, which seems doubtful.)

Short of heat-melting, still seems like it's gonna be the weight of the snow (which you always have to build to support) PLUS the very heavy planter boxes/soil/trees/etc (adding a lot of expense). Alternately, solar panels may not weight enough to require a more expensive roof, but the panels themselves are very expensive, thus adding a lot of cost.

No matter how you slice it, this is sure to add significant cost.