I plant either hostas or cannas any time, except when it is extremly hot or of course when it is too cold. I dig my hostas up and move them around all the time and they do just fine, as long as you water them well until they are established. I planted my 'Love Pat' and my 'Blue Angel' last year in November and they are doing great, I asked the lady at the nursery how I should take care of them as I knew the growing season was coming to a end, and she told me not to cut them back just to let them die back naturally, in fact you will find the BEST deals on hostas in the fall, I got those two hostas for $2.50 apiece and it was at a reptuable nursery! It was great, I am going to do a bunch of hosta shopping this fall.
Good luck and happy planting!
micke

I'd trade with you. My hosta are ugly now , in the spring there is a narrow window between the hosta coming up and time to plant canna.