Here's some info on "sexing" persimmons...no way to tell early on from the sounds of it.
<div class="ubbcode-block"><div class="ubbcode-header">Quote:</div><div class="ubbcode-body"> <span style='font-size: 11pt'>Q. I have a question about persimmon trees. I bought three pairs over the past several years from a well-known mail-order company. They were supposed to be one male and one female. All of the trees have little bell-shaped blooms, but don't develop fruit. Have I received all females? How can you tell the difference? The oldest trees are over 10 years old. How old do they have to be to bear fruit?
A. While it can take seedling persimmon trees 10 or more years to mature enough to flower, your trees appear to be ready. If the trees are blooming, then they are old enough to bear fruit. Assuming that all of your trees are American persimmon rather than Oriental, then the issue is whether you have a mix of both male and female trees. (It would be useful to know what cultivars you have planted.)
American persimmons usually bear separate male and female flowers on separate trees. Only the females will bear fruit, but you do need to have at least one male to provide pollen for fruit set on the female trees. Occasionally, persimmon trees will bear both male and female flowers on the same tree, but it is not the norm.
So if all of your trees are blooming, then the question is whether you have both male and female trees. When they bloom next year, look closely at the flowers, and you should be able to tell them apart. Both are greenish-yellow, bell-shaped flowers borne on very short stalks. The male flowers are about one-fourth to one-third inch long and are borne in small clusters, usually in threes. The female flowers are slightly larger, borne singly and are about one-half to three-fourths inch long</span>. </div></div>