Last fall I remembered to lift my Dahlia tubers. I over wintered them in the garage. They say to carefully store them, but I just throw them in a plastic bag and then hang them up till the end of March.
I always mix the tubers, so I'm never sure what color they will be until they flower. I started them in the house the end of March to go out in early May. If you start them too soon, they will be leggy.
This year they are much bigger. I left 2 or 3 tubers together for a fuller plant. They are about 18 inches high and have been flowering non-stop since the end of May.
Even the bees are enjoying them! Just make sure you remember to dead head them and they will continue to flower all summer. I think I will look into some taller ones next year.