They belong right here, Rita! Lumped by most nurseries into the "summer bulbs" category. If you find yourself getting really into Dahlias (or would just like see a lot of gorgeous pictures), there is a Dahlia Cubit here too, where many genus specific issues are discussed.
Both Dahlias and Cannas prefer warm soil, Cannas won't start growing in earnest here till up in June. I've found starting Cannas in pots very helpful. We had a couple of really dry years here (before last year's cool, wet summer), so my Cannas in the ground have dwindled. Large containers are great for them, you can easily give them all the water, fertilizer, and warmth they love. The cool temps last summer made my Cannas grow slowly whether in the ground or in pots, but those in pots definitely performed better. Starting them in pots, especially black nursery pots is great- that keeps the soil warm from the sun. You don't have to worry about getting them in the ground till the soil has warmed, about the time folks are planting tomatoes in your area. Here thats about Memorial Day.
Dahlias grow pretty fast for me, so I just plant those right in the ground. A lot of northerners do start them ahead of time because of their short season.
Where did you purchase your summer bulbs?
