I know what you mean - I've got zone 6/7 clay here that rots out all kinds of things over the winter. I use butterfly bush (buddleia) - I love the deep purple color of Black Knight. Not hardy, but lots of cannas - I can winter the tubers indoors without needing prime growing space. I fill in with ornamental sweet potato vine - also not hardy but grows obscenely fast with a few shots of Miracle Grow.

Keep in mind that in Zone 6, it is not always the cold that kills your plants, but wetness which leads to fungal attack and rot. I gradually amended or changed my soil to a mix of good compost, sand and peat, which gives good drainage of excess water, but retains a comfortable amount of moisture. Raising beds gives better drainage too. When preparing for winter, dump an additional layer of bark mulch on the ground to act as insulation, and for rot-prone plants, a little fungicide like Bordeaux mixture can be very helpful. In my zone 6A, I have yucca, bamboo, osage orange, hibiscus and prickly pear cactus. We have long cool wet springs, so if I want everything to survive, I have to keep in mind the "fungus factor".

As Don said, it's not the cold that kills alot of plants - it's the constant moisture. I have a neighbor that has cannas planted 12" deep, on the south side next to his house, and he never digs them. They multiply each year and he has a very large area of them, all started 10 years ago, when he forgot to bring two tubers in.

I was told by a greenhouse grower in my area that he has had great success with elephant ears, by putting plastic over them (leaves them in the ground), and piling manure about a foot deep over the plastic. His ee's are HUGE and multiply rapidly. He has never dug them to overwinter them.

I would just experiment with covering the crowns of different things, mulching them deeply, and see what successes you have.

Here, on the shores of lake Ontario, the "Frost line" is less than 3 feet at maximum. Our natural soil is sandy. Although, our ground does not freeze solid for 3 whole months here. Maybe 2 I would say is a bit more realistic (that's here) There's where Mulch comes in handy. Now the Freeze Line here, (different from Frost line) is about 1 foot max. I suspect it would be not much different than New Jersey.

Rick

What's the difference between freeze line and frost line?

Hi, I just made a wonderful discovery. Brugmansias - could you get much more tropical looking than that? - can easily be overwintered even in Zone 5 where I garden. This year mine grew to a lovely 7 feet tall by 6 feet wide, was covered in intoxicating flowers much of the summer, and is now happily hibernating (and cut down to a manageable size) in a cool room in the basement. There are several good websites with lots of helpful info. Check it out - you won't regret it.

Plume poppies (Macleaya) look vaguely tropical in a figgy kind of way.

For a small tree, Aralia spinosa is very tropical looking but quite hardy (at least to zone 6, probably to zone 5).

Some plants that are not exactly tropical, and quite common where I am (zone 7) might be more exotic looking at the limits of their hardiness in zone 6: figs, crepe myrtles, Nandina, Aucuba, Photinia, Vitex. And if I had the room, I would definitely grow some bamboos.

I think that the huge leabves of pawpaw make it look like a avacodo tree, and corkwood (leitneria floridana) looks like it belongs in some steamy, tropicle jungle with its thin stem capped by a large rosete of buf leaves- as a plus, it forms clumps. hardy to zone 5b. i have seen some in cultivation and they looked very tropical to me- not to mention both are very hardy.

Royal paulownia grown as a shrub instead of a tree: cut it down every spring at it'll get HUGE leaves. That's my most hardy tropical looking plant in my garden. Zero maintenance also.

Any suggestions for other plants that fits the bill? I can't possibly fit one more pot in my basement next winter.

Gunnera is a great, almost pre-historic looking plant. You'll need lot's of space for this if you decide to grow it.

Cheers, Barrie.