some genus (seed) require a cold period to mature & be able to germinate. in your case the 2 months was a period determined by trial & error to work.... IF you only stay 1 month in ref. some of the seed MAY germinate but most will not & have to be put back in the ref for another month. resulting in time lost not gained.....

I have had success germinating japanese maple trees and would like to try germinating a japanese cherry blossom seed but I do not have one on my property. Does anyone know when japanese cherry blossom seeds are ready to be collected? Thank you.

When the fruit is ripe (turning purple/black), the seeds are ripe. Usually approx mid-summer.

spynn001 - be aware that many Japanese cherries do not produce fruit because the flowers are double. This means the reproductive parts are missing, replaced by more petals. Also most named flowering cherries are reproduced by grafting, not seed. So if you find a tree with cherries and get them to grow you are still not guaranteed a clone of the parent tree. But the experiment would be interesting if you are patient enough.