This is a picture of Cascade Ken from Dan's Dahlias. The tuber was planted one month ago. I would like to prune it to make it a more compact plant in maturity. Are there instructions for that here?
When To Prune
I'd remove the four lowest leaves and then pinch the center of the top above the three leaf mark.
I'm sure there are many good links here somewhere. Here was a video I found that made it much easier to understand.