You probably don't even need to protect your Musa basjoo in the winter (only if you want to start out with the a tall stalk in the spring). The Musa basjoo is hardy to about zero (or a little below) without any protection. The old leaves probably helped but I don't think that you need to worry about the plant ever dying. But if you want to keep the stalk alive during the winter you need to use the leaf/straw method. Remember the key is to keep it dry...

WeatherGuy

You are in the right direction in terms of giving a healthy mulch to help both the pseudostem and the root mass from freezing. With the all the cold that we get here, even down to 18 degrees for about a week, I never ever use plastic as a last standing choice to preserve the pseudostem. Burlap or freeze cloth which are two products that let the stem breathe and not sweat to the point of crown rotting. I would definately invest in some bark mulch in addition to the leaves used in the covering of the root mass. Just to make sure you don't present the ground with diseased material, for spores that are introduced from leaves that are infected can spread throughout the bananas vascular system. And one more piece of advice, no manures or rotting composts as a top-dress for insulation, as that can be an invite for the wrong bacteria and fungi.

"But if you want to keep the stalk alive during the winter you need to use the leaf/straw method."

To my way of thinking, you might as well buy cheap 'Dwarf Cavendish' from Home Depot and treat them as annuals rather than letting an M. basjoo die to the ground every year.

It will take a little work where you are, but 20' of basjoo can be had.

Thanks to all for the great advice. I'm actually quite content with a die back banana. I just want a touch of tropics around my pond, which is only about 5.5 feet in diameter. A four to ten foot tall banana there suits me fine. And it's nice not to have to overwinter it indoors - too much trouble with pests!

I think I would rather have a pretty sure bet of having my die back banana come back, compared to a 50/50 shot of keeping the pseudostem and getting a taller one.

I'm too cheap to buy a new one every year, plus it takes new plants a while to acclimate from the store. I also enjoy the thrill of carrying something through the winter outdoors - I feel like I'm pulling one over on Mother Nature. That's why I have a small Sabal minor palm out there too (which is in its second year in my yard). It may actually look like a palm tree by the time I'm an old lady! ;)

I see what you're saying, watergal. You might try doing the same thing with M. sikkimensis.

Have you seen Canna musafolia? It's very banna-looking, as the name suggests, and it can get to 14' in a summer.