What is causing all my cannas leaves to turn black as if they are getting too much sun

Question

These are new plants . They are growing with nice stalks, but hardly any blooms and lots of black leaves

Answer 1

Many types cannot tolerate full sun, although many can. It is possible that you have a variety that may not like it so much.

It is more likely that it has sustained a fungal infection. This is common with overwatering. This can be especially true when overcompensating for new, or young plants.

Can you include a photo? This will help me to better make an accurate diagnosis.