Ammania sp. "Bonsai" growth factors

I have this plant and have tried it in several of my tanks. All the tanks are pretty high light (T5HO, MH, etc). I run mid-high 6's for pH and fertilize EI. The plant grows, it just doesn't grow very tall. It seems to grow one stem along the ground and form little shoots from it but doesn't seem to grow up into the tank much. Often it just gets tangled with java moss and ends up looking bad. I grow most of my other plants just fine, so it's frustrating that this one won't grow well for me. I've tried to research its requirements, but they seem fairly basic and easily met. Any tips?

Michael