I don't know much about musa basjoo, but i'm trying to grow one now. But bananas don't grow much until they get a good root system that suites them. I use a transplanting solution like shultz when I plant them, and it will form new roots quick. I have a musa basjoo that I got on fathers day this year, and then I planted it that day, and put transplanting solution on it, then now it is growing a new leaf, and another one coming up inside it. This might be my lucky banana, because I bought three others, and all three of them died.

Don't try to kill them with too much fertiliser. It seem that you're over-feeding them! Too much water will kill the roots. Too much fertiliser will burn them.
They need a lot of foliage for growing. At first, they have to settle and grow a large root system, afterwards they get more and more leaves.
If they are about 3' then they will really take off.
So be patient and be careful for black leavetips. (root problems)
Simon

thanks laterita for great advice on basjoo.I too was fretting over my new basjoos slow growth. you read stories of it growing eight and ten feet in a season. that is for established plants. do you protect yours in winter?

Thanks for the replies! I'll try to be patient. :)

I have to mulch them heavely. I create a cage around them and fill with straw. They need some air at the top of the cage to ventilate the water out. The real problem isn't the cold but the water. With enough ventilation, but a rainwatertight cage, they have survived -28C here.

Here is a link that might be useful: {{gwi:411173}}

Listen, my Banana has been through hell and back. Its just this year that it is doing wonderful. Be patient and let it get its root system growing. I find they are hard plants to kill. Oh, and watch the watering as they tend to like it on the dryer side. Just lightly moist, with good drainage. Diana P.S....They love the sun

Wow, your banana looks great! That's kind of what mine looks like, only mine is on a smaller scale.

I thought I read that you almost can't overwater them! Oops! Maybe backing off a bit on that will help.