Why hasn't my Prunus incisa kojo no mai flowered for the second year running ?

Hi Swaami and welcome to GOY.

I know very little about these plants but as you have two younger plants which *are* in flower, I'm wondering whether 9 years old is just 'getting on a bit' for this plant. It seems that P. incisa is considered to be mature at about 3-4 years old. None of the references I've checked mention age-related problems with the Fuji cherry but the information you've given does tend to point that way.

Perhaps someone else will come into the discussion with some better info.

Hi! I agree with Peteg, there are several plants which "die" around the 10 year age, so it's a good job you have the cuttings. I would dig it up now and replant with some other plants. This seems to be a bit of a slow growing plant, but once the cuttings are bigger, you could then replace the plant to where the original was. By replanting with something else for a little while, it gives the soil a chance to rest. Btw, take this opportunity to dig in some compost.