Hi, I have 2 potted black bamboos (nigra?) and they are both flowering. Is it time for the black bamboos to flower at this time? On one pot with 8 stems, 4 are black and flowering and the other 4 are green with no flower. Should I just cut out the black ones and let the green ones grow or will they turn to flowering too? Also, I cannot find the seeds, I opened the flowers but nothing inside.