I'm panicking too because I have unID cannas that I'm almost ready to burn because I don't know if they are supposed to be variegated, all I know is they always have been. So no answers,only more questions.

-Anyone know about cross contamination-how far apart to space plants to avoid infection? I have cannas all over in separate places and don't know if that would make a difference at all.
-Anything organically to clean up the soil if you had infected plants?
-How long before you could replant cannas?
I bought some labeled "Cleopatra" that are coming up looking like my Phaison (and is Phaison just a walking yellow mottle virus then?)-If the leaves were supposed to be green and were virused would the STEM be red too? It seems like I've gotten a lot of mislabeled cannas-

BUT if they are diseased, they are so gone-I'll destroy all of them and start fresh. That's my only advice.

It looks like virus to me, I'm afraid. Virtually every canna I've bought this year so far has been virused, even stock that was supposedly from US and virus-free. It's a huge problem here in the UK.

I am reluctant to get into the canna virus issues at this forum but it might be helpful to at least point out some personal opinions relative to the subject. "All" present day collectors, botanical gardens, commercial producers as well as the more informed home gardener face the same problem. No canna grower is exempt from this dilemma. That dilemma is WE now can put a name to the problem. Only a few years past, the plant symptoms were explained away by both our universities pathologists and local plant inspectors as soil deficiencies, nutrient deficiencies or one of any number of pathogens. In some cases, these symptoms "are" a result of the aforementioned causes. In over 35 years of growing and getting phytosanitary certification for cannas I NEVER heard the word canna virus until shortly before 2000.
For those who are now growing cannas, you can expect to find most purchased cannas to have been exposed to the possibility of canna virus infection. Although most of us never heard of canna mosaic it was identified in the United States back in 1948. Canna yellow mottle was identified in Japan in 1985 and in the United States in 1986. Testing for canna virus is very expensive and must be done on a plant by plant basis. If tests prove to be negative, there is no guarantee to how long the plant will remain virus free. We do not have a good handle on transmission rates or means. Each virus has its own individual characteristics. Only time and research monies will expedite these efforts.
For those of you who wish to discard and replace your cannas, good luck. Not all is BAD in Mudville. Past experience shows that many cultivars are "tolerant", rather than immune, to some - if not most - canna viruses. We often see moderate to severe symptoms in the cool growing conditions, and as summer temperatures warm the symptoms tend to decline. The plant ultimately grows and blooms quite nicely. I think you will find, depending on your own growing location, some cultivars will grow quite well (tolerant for your area) and you may find some which must be discarded.
I am sure that many of us grew virused cannas for years and were basically ignorant of the symptoms we observed, but I am positive the situation is much more prevalent today than in the past and suspect we are seeing more than one virus infection in the most symptomatic plants.
Two other quick points; I am not aware of any canna virus being transmitted via the soil, and the variegated cultivars (chimeras) are not a result of virus, although that does not exclude the presence of a virus infection.
Regards, Kent