Things I am going to try to leave outside, will overwinter bulk in garage or house, but am curious:
Bird of Paradise
Heliconia
Split leaf Philidendron

Support/background plants that give spring color:
Quince
Camellia
Spirea
Azalea
Sweet Olive, just for the smell

Things I killed:
Tree Ferns

Magnolia macrophylla is one of the most tropical-looking hardy trees. Both the leaves and flowers are enormous. I remember seeing it growing in Ithaca, New York (zone 5?) but it was growing in a sheltered location.

Catalpa, Paulownia, and some other hardy trees can be cut to the ground and will resprout with fast-growing juvenile shoots with enormous, tropical-looking leaves. Paulownia can grow to 15 feet in one growing season with leaves to 2 feet across. Start with a 2-3 year old seedling that has well-established roots but not a big trunk yet. I plan to try the same with mimosa next year (seedlings from a neighbor's tree are sprouting all over my garden this year).

Ailanthus responds similarly and is even more tropical looking, but suckers aggressively from the roots and is dangerous to invite into one's garden. Sumac is a native alternative for a similar look, although it is also somewhat invasive.

This year I'm growing Aralia spinosa from seed, which is another very tropical-looking hardy shrub with large compound leaves.

One plant I rarely see mentioned is skunk cabbage. The leaves can get quite large.

All of the above should be hardy to at least zone 6a.

For your climate, I might go with magnolia virginia, skunk cabbage, catalpa, possibly bald cypress, bigleaf oaks, super hardy rhododendrons, hollies, and ferns.

Many gingers are hardy for us here, hedychiums, costus, curcumas...bananas are perennial, split leaf philodendron is evergreen, and thee are several landscape bromeliads hardy here

Variegated crinum is a killer accent

I tried to email you directly, put couldn't find a link to do that on your GardenWeb page.

If you search the Banana forum, you will find lots of info on growing Musa basjoo.

Having said that, here is how I grow mine in Zone 6/7. The first year, the plant was unprotected over the winter. It came back the next spring, but didn't grow as tall during its second summer in the ground. The last 2 years, I have built a wire mesh frame & filled it with dry leaves. Last summer, it grew quite well. It also gets a lot of fertilizer. It is hard to say how much the improved growth is due to 1) winter protection, 2) fertilization or 3) the plant getting larger each year.

In your area, I would definitely mulch it heavily with pine straw and dry leaves.

Hope that this helps,

Dan

Adam

Which variety of voodoo do you have? I have sauromatum venosum and love it, but I've always dug the bulbs up in the fall; they'd probably be fine but I didn't want to waste my 6 inch beauty trying to overwinter it.

Alan

The plant size is dependant on the corm size, as it grows, so does the rest. Cutting back in dormancy should not have a big affect as leaves re-grow rapidly when the temps warm...

My favorite hardy tropical plant, that's not hardy, is the canna. Sure it must be dug up in the winter in northern zones, but that's a very simple, easy process.

And few plants match the canna for "the tropical look". I consider it a must.

Good luck!

catalpa, especially with the unique hanging seed pods.

petasites, rhubarb, hostas

Vinca minor 'illumination' is a unique yellow/green variegated groundcover.

Sambucus racemosa Sutherland (Sutherland golden elder)

Sumac

hardy grasses tend to look tropical,

Paulownia (empress tree) grown as a stool (cut to the ground each year, keep to a single trunk and it will get huge leaves).

colorful barberry's such as cherry bomb or gold nugget.

I read that in general, we tend to think of plants with overly fine foliage, overly colorful foliage, or overly big and bold foliage, as being tropical in appearance. On that note, maybe even garden asparagus with it's fine ferny foliage might add to the tropical look.

Also, there are different types of tropical climates. Plants like yucca glauca/yucca filamentosa, hens and chicks might add to the desert tropical look. Last year I grew these in pots beside a red cordyline.

The fun thing is to combine hardy plants with real tropicals and I agree, a few cannas, banana plants, even a palm tree bought in the houseplant section of the local store adds to the tropical look. Add flowering annuals, since most originate from the tropics such as hot colored marigolds, petunias, basically what ever you like.

Anything vining tends to look tropical such as clematis and other vines. For a quick growing annual vine try hyacinth bean with it's red flowers (and edible beans afterward).

I also have a copper plant which was in the 'proven winners' section at the local nursery. I found out it's actually a tropical shrub so I overwintered as a houseplant and it's going back outside this summer.

Glen