You're not looking after it too well are you? They are neglected in the wild and seem to do ok.

well what i learnt from fig trees, is that root space is the main factor that controlls if it fruits or not(if the fig roots are squished then it produces fruit) so mabye your native hawthorn needs some environmental factors needed to be checked over. the best place to look is in the wild,dose it need more or less light?dose it need to be in a small or large space?