Hostas should do just fine in Zone 3. It's the Zone 8 folks that are pushing it lol.
Generally speaking, hostas with sieboldiana heritage are better off in the north. They are a short season plant. They are in a hurry to bloom, set seed, and the evenual heat of summer will cause heat dormancy in the warmer zones. plantagenia would be the opposite. They bloom late, and are from a warmer climate, and will grow huge for you if you plant them with more sun. Of course, there's all the other's that bloom throughout summer, and the hundreds of hybrids (thousands?) but, that is the simplest way to explain it.
This lack of snow cover isn't doing any of us any good!

Very interesting about the heritage differance. Thanks so much!

Here in the far north, where at times I've seen temps dip down as low as -45f, seldom have I ever lost a hosta to winter's cold ... though, the odd plant has faired poorly when we've had winters without much snow covering. But, I guess this really doesn't answer your question regarding there being types that are more tender.

Terry

dormant is dormant ... frozen is frozen .. i don't see what difference how frozen or how dormant it can get in a given zone ....

I WOULD GUESS its the other half of the equation .. not the winter half .. but whether the growing season is long enough for the hosta in summer ... if they cant flower, and start the food storage process in late summer/fall .. then they wont store enough food to come up the next spring .... it is my understanding that they come up on stored energy .. ergo .. if they dont store enough.. they do not prosper the next year... and would eventually dwindle down to nothing ...

but what the heck do i know.. ken

Frozen is Frozen? I know the lack of snow cover is an issue because even though it can get sub zero there are also days it gets above thaw. On these days the snow keeps everyone sleeping. If they begin to wake then get re-frozen there is trouble. Some plants must have roots, tubers, what ever, that can stand a certain low temp. beyond frozen better than others. The length of the growing season is logical, but I think the lowest temperature is a factor. But I know nothing. I know I lost an Autumn fern the second winter. Could have been my growing season was too short I suppose. I lost mums one year that were in the ground for four. It happened after a no snow cover winter. I am babying an Endless Summer that, once settled in, should be fine here. This is its third winter in my garden. It is the first I did not mulch it.

arcy's comments pretty much sum up what I have to say ...

"frozen is frozen" ...
Guess that is true until it reaches the genetic tolerance of the plant.

"i don't see what difference how frozen or how dormant it can get in a given zone" ...

There can be large variations between individual winters and the ability of plant material being able to survive what is dished out. Obviously, snow covering makes a HUGE difference in how the ground is protected from severe cold. Get an early dump of two feet of snow and your tender perennials usually come through smiling ... get -30 f upon barren ground and they're history! ... along with alot of other plants!

"whether the growing season is long enough for the hosta in summer"

Yes, a very short season would not properly allow plants to adequately prepare for winter and store up enough energy. Though, even with my shorter summers, for the most part my hostas are looking pretty tired by the time hard freezes arrive in October.

arcy said: The length of the growing season is logical, but I think the lowest temperature is a factor. But I know nothing ... mmmmmm, you put together a pretty good paragraph upon the subject, so don't knock yourself there arcy!

Terry