This might depend on where your source for seed/plants is. Both of these trees have very wide ranges in North America, including quite far south in Florida and Texas into areas where winter frosts become intermittent. Why not grow Asian persimmon instead...there are even non-astringent varieties available. Americans are very seedy as well as astringent until very soft, and the tree reaches a height where picking becomes difficult.....
Also remember that both of these species are native to a region with (usually) regular to frequent summer rain and will probably need regular irrigation or a moist/riparian niche to thrive in a Mediterranean climate....
As long as you get enough cold weather for the tree to go dormant for the winter you should be fine. What affects pecan crop, in my observation, is summer rains. If they get drought stressed, the nuts just don't fill out and you get a poor crop. If they get adequate water (and this can be made up by irrigation), they will yield. Even then, pecans have a tendency to mast, giving a generous crop one year and then slack off the next year or two.
I wanted to plant the American Persimmon further out almost for sentimental reasons to go with my Paw Paw, Black Walnuts and Black Locusts (I used to live in the States) and as pig fodder from high above. Im definitely going to plant Kaki also.
Plenty of rain here (1500mm/75 inches) and springs so we´re good on water. Where I live is like the coastal Pacific Northwest.
Thanks, Ill look for warmer weather pecans!
Why work hard when god made so many mongongo nuts? - !Kung
The notion that man must dominate nature emerges directly from the domination of man by man - Murray Bookchin
C'est drôle comme les gens qui se croient instruits éprouvent le besoin de faire chier le monde.-Boris Vian
El hombre es la naturaleza que toma conciencia de sí misma -Elisée Reclus
I am from zone 8 in Georgia, and they grow pretty good here, enough to be worthwhile. There is a much higher concentration of pecan trees south of here, more in the zone 9 area. A little bit warmer, a little bit milder winter would probably be ok.
I agree with what the others said about where it is sourced from will play a big role. Our trees were planted by the crows. They picked up pecans from a local established tree and dropped in the area, and when the land was cleared they kept them. It was very natural selection. Some years they produce in massive ways, other years crops are small. It has been one of the wettest years we have had in a long time, time will tell whether that creates a good or bad crop.
Trees from farther south, maybe florida would better suit your area.
We appreciate them for the pecans and we use the wood to smoke meat.
You know, as far as persimmons needing a frost, I think what that means is the fruit isn't ready until late in the year. The actual physical frosting has less to do with it than the age of that particular crop. Now then, that's my opinion, I might be wrong, but in any case, it's worth what you are paying for it! Best, TM