I don't have an answer to your question, however I can say that their native Japan has a very reliable and clearly defined 4 seasons. The Japanese have all these sayings about when such and such a directional wind blows, spring has arrived, etc.

My mother-in-law ate goumi berries as a child in a somewhat mountainous region of Fukushima prefecture, which is cool temperate, maybe comparable to zone 6 or maybe even 5.

Probably more hardy; they are a compact little blossom on a shrub that is an early bloomer anyway.

BTW - if anyone would be kind enough to send some goumi seeds my way, I would be delighted.

Thanks, larry and yukkuri. I'm sorry to say that I don't have any seeds to share at this point, but, if you'd like to have fruit sooner rather than later, you might want to consider buying one of the named varieties that are propagated by cuttings. I planted three goumis last year -- a Sweet Scarlet, a Red Gem, and an unnamed seedling. All prospered, but only the named varieties have fruit buds this year. I'm sure that the seedling will bear fruit in time, of course, but you'll more than likely have fruit much sooner on a Sweet Scarlet or Red Gem.

If you're still keeping an eye on this thread, yukkuri, I thought I'd retract my statement about my seedling goumi -- it's currently blooming profusely. Interestingly, it leafed out before beginning to open flowers while the named varieties began opening flowers before leaves. I'll be curious to see how the fruit compares -- that is, if I'm able to keep the birds away from it.

Mine were starting to bloom when we had our last frost, it got down to the mid twenties. They did not seem to suffer. It seems that most of the early blooming fruit plants only open some of their flowers early. If the weather kills them then other flowers open a little later. My goumis are in full bloom now.

Yukkuri kame - I can send you cuttings but you want them in February while they are dormant. Seeds need a winter period to sprout also and I never see seedlings under my trees so seed sprouting must be tricky.