Sorbus ulleungensis: this endemic to Ulleung-do Island between Korea and Japan. It has large quite sweet berries. I hadn’t noticed that there was a row of this species planted next to the garden entrance! The garden had collected this and other species from an exhibition there (see my article on Dystaenia takesimana here: https://www.edimentals.com/blog/wp-content/uploads/2020/03/Dystaenia_fin-3.pdf)