I acquired 2 pomegranate cuttings about 4 years ago. One of the 2 plants is now producing flowers but the pomegranates drop off when they're about an inch big. Is there anything I can do to help the pomegranates reach maturity? I was told that pomegranates are self-fertile but I'm now wondering whether the issue is that only one of the 2 pomegranates is flowering. Thank you!