I have a self-pollinating apricot tree (var. Hargrand) that is now in its 4th year since being planted out as a stick. For the past couple of years it has flowered & set abundant fruit which, however, have almost all dropped off by this time of the year. Any ideas as to the cause & potential remedies? The people I bought it from think its the squirrels, tho that doesn't explain why the fruit is still lying on the ground. Elsewhere I read that it could also be due to embryo abortion due to incomplete or non-fertilization of the flowers, meaning a second cultivar is required, which doesn't quite square with this being a supposedly self-pollinating tree.