I potted up canna tubers the end of February. They are looking healthy with large leaves, but when will they bloom? How long after the leaves form does it take to see the flowers?
They reach full height and then bloom. So it depends on the height.
Canna can be 4-12 tall.
It's also a bit early for blooms in most climates...
Nightrider is right. You didn't say whether you put this canna outside or not. They need lots of sun and heat and eventually water. The earliest I have had any blooms from putting the rhizomes directly into the ground has been about July in VA and also July in IA,but I have had it as late as Aug. My daughter in Texas put hers in the ground in April and still hasn't any blooms. Usually plants started indoors have that head start and bloom before those rhizomes planted directly to the ground. The true answer to when they bloom is "not soon enough." Once the leaves have attained their height, nothing seems to bring on the blooms like the rain. Water then all you might, but the rain seems to bring on that flush of blooms the best.