May one make the brocha on a blossoming fruit tree that in previous years has not been capable of bearing fruit, most likely due to lack of cross pollination. The tree has flowers but no fruit develops.
We will not make a bracha on a blossom from such a tree. We can only make the bracha if a fruit will come out of this blossom. Since there will not be any fruit coming out of this blossom we cannot make a bracha on it.