I am in zone 8 and I manage pretty good with them in the ground. If I had a problem with that, I mean if I were loosing lots of Hostas every year I would just put them in pots. If you plant your Hostas in pots more cold air will get to the roots. Remember they must have good drainage, they rot easy. I never use mulch in the winter, but in summer to retain moisture and then remove it in the fall along with the dead leaves and all.
Tony Avent from Plant Delights Nursery has a lot of good articles out but the one that has helped me the most is 'HOSTAS FOR WARM CLIMATES', there is even a list of hostas you can choose from but along with his advice I like to evaluate some of my own choices and just see what happens. I hope you will try a few at least, of the low chill variety. My lowest, low chill was 'Sea Thunder', I have several.
http://www.plantdelights.com/A...
...........SEA THUNDER
