Warning : Costco trees (2 years apart)both had to have severe root prunings which set trees back. Definitely left in pots too long plus tree no. 2 which is just putting out new growth while tall was spindly and definitely bait and switched supposedly 3 gallon. No way, upon repotting when I got it a 1.5 - 2 gallon root system was put in a 3 gallon pot......

baby yuzu or yuzu hybrid possible (calamondin?) in red cup from fruit I ate off its mama. Very very slow grower

Hmm, interesting. It's hard to tell from the picture but the leaves don't really look too similar to any of the Yuzu seedlings I have grown.

My Yuzu seedlings seem to be able to survive outside pretty good in zone 8a, Olympia, WA. I don't know, it might be able to grow outside where you are, in 7b, if you have it close against a wall.

But a Clementine-Yuzu hybrid I had was not able to do so well. It slowly declined after 3 years and finally died after only a mild winter.

I might have had more luck with yuzuquat.

Is your Owari just starting to bloom now? Usually they bloom in late winter/early spring.