Prunus spinosa insect-pollinated. The fruit, called a "sloe", is a drupe in diameter, black with a purple-blue waxy bloom, ripening in autumn and harvested – traditionally, at least in the UK – in October or November after the first frosts. Sloes are thin-fleshed, with a very strongly astringent flavour when fresh. "Prunus spinosa" is frequently confused with the related "P. cerasifera" (cherry plum), particularly in early spring when the latter starts flowering somewhat earlier than "P. spinosa". They can be distinguished by flower colour, creamy white in "P. spinosa", pure white in "P. cerasifera". They can also be distinguished in winter by
Prunus subg. Padus "Padus" is polyphyletic and is therefore invalid as a genus, subgenus or anything else. In Finland and Sweden, the blooming of bird cherry ("Prunus padus", Finnish "tuomi") signifies the start of the summer for many people. In southern Finland, this normally takes place during the two last weeks of May or very early June. North Dakota State University agriculture information page about "Prunus virginiana" Prunus subg. Padus Prunus" subg. "Padus (bird cherries) is a subgenus of "Prunus", characterised by having deciduous leaves, flowers 12-30 together on slender racemes produced in late spring well after leaf emergence, and small, sour fruit