Photos taken on April 1. Prunus 'Spire' arose as a seedling of Sargent Cherry (Prunus sargentii). From the superabundant blossom it looks like it could be a cross with Yoshino Cherry (Prunus yedoensis).
Grown for its early flowers and upright habit. But on older trees (below) it opens out and does not look so very spire-like.
Close-up showing the red eye of the blossom and the young leaves, bronze when they emerge but often with bright green teeth.