I have a container grown Hosta that's done very well this year, (thanks
to some slug eating Red Legged Frogs), but now that it's been cold
(freezing at night) and raining in the Pacific Northwest (Zone 8b), the
leaves on it have started to brown and yellow- supposedly this cultivar
is cold hardy. Is this normal for a Hosta when the days get short?

The other plants in the container are happier than ever, but I've moved
it to a warmer, drier, place for the time being.