I’ve been studying this shrub/tree for years trying to figure out what it is – I’ve finally decided that it’s a type of English Hawthorn. (For a long time I was stuck on some kind of Ribes – gooseberry or flowering currant – because the leaf shape is similar). Based on photos I’m thinking this could be ‘Paul’s Scarlet’, but I’ll probably never know for sure. This shrub is described as needing full sun but is sited in full shade, and seems quite happy other than being open and leggy; it flowers reliably after leafing out every spring. The thorns are impressive, and I’d consider propagating it except that I’m not sure I want such a thorny tree anywhere else in the landscape.