I have 4 types of purple dahlias this year. I thought I would post some photos of them so you can see the differences... Here are: (from L to R) Fremont's Memory, Diva, Taboo, Jason Matthew. I had Thomas Edison but I didn't stake it properly and it fell over and died :-(

As you can see, they are all a very similar color. I had a very hard time getting a photograph with them looking purple - most of the time they come out red in the photo. Fremont's memory is much less ordered than the others. Lots of blooms on this plant. Diva in this photo is not fully open - you can see many petals are still folded in. She doesn't have as many blooms, maybe 1 or 2 at a time. But the stems are really, really strong and stiff. Taboo is smaller, but the petals are so rich, they look almost like velvet. Jason Matthew is the reddest of them all, and while my plant is covered (COVERED) in blooms, I find I like this one less and less. They just look kind of ratty right away.

What do you have?