The birch nearest the gate has doubled in size. The middle one is smaller but healthy. The third drops leaves early and produces a cautious flush of growth each spring.
Three small differences
The first has deeper soil. The second gets morning sun. The third sits where two roofs concentrate rain, then dries faster because the fence blocks air. The planting plan did not show any of that.
I could replace the third tree. For now it stays. A garden is allowed to have one unresolved thing.