Which one of these two would be the bigger spreader? I'm going to put one in a dappled shade spot.
What are your soil conditions? I thought cyperus needed to be in pretty damp or soggy soil, such as along a river bank. Clumping bamboo would not necessarily do well in that situation.
Conditions would be shady and a bit moist. Oh, would you happen to know if cyprus and bamboo are in the same family?
Bamboo is in the grass family (Poaceae); Cyperus is in the sedge family (Cyperaceae).
Bamboo don't like their feet to be wet or in standing water continually. Moist is ok because they do like water. You'll have to determine whether your conditions are either moist enough for cyperus, or not too moist for bamboo.