It appears to be rust, I would cut off the bad leaves, other members will give you better advice.

Hi Sandy,

Christine has hit a potential issue for you to investigate. I have observed rust on my cannas before and I have seen perfectly round brilliant orange, fuzzy, specks, particularly on the backs of the leaves. As the rust grows and spreads the leaves get those lesions, which cause tissue necrosis in the leaf and it eventually dies, usually spreading from the base of the plant upwards. I found this publication online:

https://www.ctahr.hawaii.edu/oc/freepubs/pdf/PD-96.pdf

I am not completely certain if thats what's going on. I am new to growing cannas. I feel like cultural practices (like irregular watering) can make the leaves look rough, however rust has that distinctive bright orange speck, in small numbers at first and then growing in number and the leaf dies eventually. I have seen rust on stems at the base of the plant also.

I have not lost plants to rust, however from what I have read it is possible. I have a copper based fungicide for treating for rust and the occasional black spot susceptible rose that I have lingering in my collection (almost all of my roses are no-spray and extremely disease resistant, however I have held onto a couple of wimpy favorites). I remove and discard the leaves also (in the trash-not compost pile) and keep scissors disinfected to keep from spreading it from one canna to another.

Good luck!

Nicole

Thanks for all that info. It looks like rust is a possibility so I cut off the affected leaves. But from what I read wet soil in high humidity is a factor in rust and that's the opposite of what I have so I'm not sure.

I like the lighter colored flower, it's different from my other Cannas, so I'm hoping it won't spread over the whole plant because then I don't know if I'll make the effort to over winter this one.