Japanese plums with the highest chill hours?

[krismoriah]

Good question.

Fedco says that Elephant Heart is Z4… and a good rabbit hole adventure on Google will show results from nurseries from it being low chill to Z3 and everything in between… literally no consensus on nursery descriptions.

Then there is this forum with a good thread on the subject-

Japanese Plum - frost hardy - early ripening?

Back around 2002, I purchased and planted two Japanese Plum trees. I could not tell you for sure at this point what varieties they were… but one had reddish/purple fruit and the other yellowish/orange fruit… and they were both excellent for fresh eating or preserves. We loved them. The problem with them was… here in Tennessee zone 7a - we regularly have frost in March and even early April… and they bloomed (one around Feb 15, and the other just a few days later). They both grew well here an…