Asian and American Persimmons in North America
Persimmons are one of the easiest fruit trees you can grow in North America. Not only are they relatively pest and disease free, they awaken from dormancy late in the season, which allows them to frequently avoid frost damage in the unstable climate that is commonly experienced on this continent. The American species (Diospyros virginiana) is also quite cold hardy, with some well-established trees from a northern strain surviving temperatures below -30F. However, young trees may benefit from protection and – with the exception of regions that experience less heat but an unusually long grow season – the earliest ripening varieties require at least 2250 Grow Degree Days for a partial crop to have a decent chance to fully ripen on the tree. This often discourages people below zone 5 from experimenting, but as long as they have enough time to turn yellow, improved selections should be able to finish ripening on the counter.
Asian persimmons (Diospyros kaki), and their hybrids, require a much longer grow season, but like the American species, they, too, have a low chill requirement. This allows them to be grown as far south as central Florida with little to no trouble, outside of birds and mammals, of course. Hybrid persimmons tend to be favored, since their American parentage often gives them a more complex flavor, but like the Asians, their fruit are usually larger and their trees are less vigorous. They need to be quite soft before they become edible though, since their American parentage is also the reason why every single one happens to be an astringent-type.
Wild American persimmons are generally self-sterile and produce male and female flowers on separate trees (dioecious), but the Asian persimmons that are available in North America, as well as their hybrids and most American selections, are parthenocarpic, which means they produce seedless fruit in the absence of a pollination partner. A few varieties will occasionally produce male flowers as well, which seems to occur on weak branches. The Asian variety 'Chocolate' and the American variety 'Szukis' are known for being very consistent in this regard, so they are often chosen as a pollinator when one is desired. In fact, a large percentage of the Szukis tree may end up being male. However, most people would rather have their fruit without the seeds, but there is one reason why having a pollinator might be preferred. Some Asian varieties are of the pollination-variant non-astringent type (PVNA), which means that it is basically an astringent persimmon that lacks flavor if it has not been pollinated, but if it has been pollinated, it is more equivalent to a non-astringent persimmon with a flavor that is often considered to be superior to the other Asian varieties.
More information can be found on the Persimmon Variety page.