You do have some very good contrast there, and it looks like those bamboos can grow so much better. Mine are pretty dense too, but they tend to fan out as the shoots that emerge from the perimeter tend to grow at a slight angle away from the center of the grove.
Parvifolia
Atrovaginata
Propinqua beijing
Makinoi, really having trouble with running as the grove takes up less than 1 square feet of space with barely any rhizome growth this year which was its 3rd season in the ground. It was taken outside of the pot before being planted too, even though it doesn't look like it.
Even my neighbor's fargesia rufa is running at a faster rate than makinoi at this point.
