I have two parsley hawthorns and only one flowers and produces fruit. I'm guessing its a girl and the other is a boy. I have had the boy about 4 years and its about 7' tall. The girl is roughly 3 years old and 4' tall. I also have a washington hawthorn that has never flowered or fruited. I'm not sure but I think only the females flower and produce fruit. The males may flower but at an older age. I have noticed the girl that produces fruit has smaller leaves than the male. The two trees came from different sources so who knows, but I think its just a boy girl thing and the boys mature later.