potted bamboo

I have some black bamboo that I got via Craigslist from a local gardener. It was in garden soil in a 5 gallon pot that had rooted a bit into the ground below. It was in mostly shade. I put in in potting soil with some moisture-retaining crystals in a 16" pot in part shade. I've given it all-purpose liquid food.

It's done nothing except lose some leaves. Surface roots have spread out in the pot. It want some growth upward.

Any advice is welcome.

Black Bamboo is a running type bamboo. Which means it sends out underground 'stolons' or 'runners' that can come up some distance from the original plant. If not contained it might become a pest. It is also a very beautiful Bamboo. The stems or culms are jet black when mature. They like the soil to be moist pretty much all of the time, but not soggy wet. It also grows faster when the temperatures are warm. We have only had about two weeks of warm weather, so give it a little more time. Also Bamboo like to be fed with a plant food with more nitrogen. So if you have not fed yours yet, this would be a good time put some plant food on your Bamboo. "Gro Power" works very well for this about every two months. I would suggest keeping your plant in a contianer, unless you have some sort of root barrier in the soil to keep it under control, it can be a real pest in the wrong place, if it gets out of control.