I planted 2 centenial rhizomes this year. On of them has 2 shoots coming up but the other one has 5 shoots. They are not growing very fast. I assume it's because we have had hardly any sun yet. Should I cut off some of the ones with 5 shoots? Two of them are 3 inches tall, the other 3 are just coming up. If I do cut some off, the big ones or the little ones? I read it both ways.