no idea- used to be a huge ponderosa pine there and the birds crapped mountain ash seeds and 25 years later they keep replanting. Probably have 20 of them growing in yard now...
They look nice. It did not look like western Mtn. ash (S. scopulina), lacked shiny leaves, and leave looked to big for European, and to small for American, so was figuring you planted it, and thought maybe 'showey'...but looks to big for it...so wonder I shall.