Compare : Commelina virginica Commelina erecta Commelina communis
Major differences is the color of the small lower petal (blue or white) and whether the plant has a reclining or erect habit. Two are native and one is an alien. I guess there is no point of the erect ones reclining if the joints are not going to root. I am on the lookout for the two native species.
Thanks for all the good info. Ive been able to identify this plant as the native wildflower/herb commelina erecta. I wanted to let this beauty make a home in my rock garden but was hesitant that it might take over! Your time & knowledge is much appreciated.