Beautiful, I was looking around and most websites say between 4.5 and 6 feet. Where did you buy the packages? I was reading that they are suitable to grow as a house plant? Is that true of all dahlias or just this one?
If I drove for 90 minutes I would not be in my zone anymore so purchases would not be good. I know up north people are looking for HARDY, and the more certain the better. Around here any old thing will grow happily. I don't always get a good cold spell so some dormants are not too happy. This year they should be happy, very happy. They should be having a party in the soil, hip, hip happy!