Serviceberry leaflets turning black

I bought two serviceberries from Burnt Ridge this spring, Northline and Smokey. One of them was a multi-stemmed plant about 10" high and the other is a single whip about 14" high.

The whip has been struggling and now it appears that the new leaflets are turning black before they can get bigger.

Does anyone know what this might be? Any thoughts? I’m am concerned that I might lose it.