Have you fertilized them? Also, did you plant them 1ft deep, or is the soil 1ft. deep?
Your daytime temps will determine how fast they grow. I planted mine in the spring and three varieties are just now starting to send up blooms. Two others probably won't bloom until August.
We had a long cool spring and we're just now getting warm weather. I've seen a huge difference in my plants the last 2 weeks.

I live in WA and I planted mine in Late April. It has taken my canna plants a while to start growing. They also have started to take off in the last few weeks. No blooms yet. I'm expecting August blooms.....

I was under the assumption that if they were planted too deep, they would not bloom. Am I correct? If not, please advise.

I keep mine about 4 inches deep. Most are blooming already.