Japanese Plum - frost hardy - early ripening?

[OldKYHomestead]

Candy Heart Pluerry

This is how Andy Mariani describes it in his blue booklet: Origin Luther Burbank. Mr. Burbank had given this plum, an exclusive variety, as a gift to Catherine Bunnell, wife of once prominent law professor Wm. Gorrell at Boalt Hall, Berkeley, probably in the early 1900s. The only known tree is still clinging to life in the backyard of the old Gorrell residence. CRFG was recently [in 1994] given the opportunity to save the variety by repropagating it. The plum is said to resemble Santa Rosa, wh…

I went looking again, and this post here has the most information that I can find. Sound like it was almost lost because of the problems for commercial growers… but some of those challenges feel surmountable for a home grower with one tree.