Since I had colored lights, I could not just simply coloramp it. I had to use a similar coloramp to see what my material would look in the correct color with lights. I took that and mixed it into my original using the value of my new color.
Thanks. Yes, it is a curve. I modeled a rough shape with metaballs, and grew an ivy up it to get the initial shape. Then went into edit mode and removed most of the ivy segments, rearranged and repositioned the remaining segments, and tapered the main leader so it would be larger than the streamers. For the shader, I found that a volume emission gave the best results.
I accidentally cut off quite a bit of the lightning; clipped it into the ground, doh! I’ll revisit this render at some point with a proper landscape. And I’ll likely spend more time working on the form of the lightning.
If anyone else has a good technique for making lightning, let us know! This is just what I came up with :).