North American Fruit Explorers mailing list at ibiblio

[Jwlehman@aol.com]

In a message dated 10/12/2011 10:42:53 PM Eastern Daylight Time, 
filtertitle@aol.com writes:

> Does anyone know if there is a black walnut (J. nigra) that is 
> self-fruitful in more-than-just theory?
> Thanks,
> Steve; NJ 6b/7a
> 

Steve,

Jim McKenna answered this question also. 

There is no hard data that I am aware of.  In general, all walnuts are 
capable of self pollination.  Because their female and male flowers bloom at 
different times, they tend to out-cross more than 90% of the time.

If you examine the blooming habit of different cultivars, those that show 
the most over lap in female and male flower receptivity and pollen shed would 
be the ones that can self pollinate.

Because black walnut pollen is very light and prolific, and because there 
are so many walnuts around, it is not typically considered a necessary trait.

Jim