Hello! We're harvesting plums off these shrubby trees. In the March, the white fragrant flowers clothe the plants and now there's sweet fruit to be picked. I'm curious if they're Prunus americana. There are more than one tree in the area that bear all the same type fruit and have the same characteristics so I'm not inclined to think they're a hybrid cultivar. Fruits are 2-3 cm. Turn yellow when ripe. Leaves are small compared to Italians. No thorns noted. Any input would be great. Thanks!