Amelanchier canadensis

Blossoming in the garden today - the closest, in flowering terms, we seem to get in Canada to the glorious blackthorns I recall from England. The Amelanchier leaves do appear alongside the blossoms, unlike blackthorn, but take a couple of days to unfurl so for a brief period there are bare stems and branches with white flowers. The fruits are beloved of birds as they ripen. 

"Out west" other species of Amelanchier grow with tastier fruits (serviceberry) that are harvested for jams and pies but for some reason that do not "do" well in Quebec. A. canadensis is the native species hereabouts.