I remove any seed pods that have formed and leave the stalk until it starts to look tired and ugly. It is still producing food for the rhizome. I would recommend keeping the colors separate because if you don't, you'll have a brilliant idea on or about Jan 13th, to plant them out in separate colors, and you won't be able to tell what is what. :-)

I've done it both ways. If you leave the seed pods on they can make for a nice effect. The canna will bloom again whether you cut the seed pods off or leave them on.

MichaelAT

I suggest you leave the seed pods on also after they brown cut them and plant them in spring. the seep is very large and takes a long time to geminate but once it does it grows very very fast. i start seeds every year and by fall my little seedlings are taller then me and are blooming