Well, it is a Cornus but hard to say which variety.

Agree with Landgirl - definitely Cornus, possibly one of the C. alba varieties, I'd guess at Cornus sibirica because of the redness of the leaves right now, but I'm only adding this answer so I can say the pot its in is too small or certainly will be by next spring.... check if its rootbound and repot if necessary. Best in the garden, its a large shrub.

It does look like Kesselringi because of the black stems