I have a 3 year old serviceberry that for the past two years has shown fall colors by around the same time, June. I had applied a herbicide at too high of a rate last summer which I thought caused the issues. All looked fine this summer until the last two weeks when the plant looks like it's in full fall color.

Premature fall color is an indication of a stress of some kind. I would suspect poor root development being relatively new. If balled and burlapped, lots of roots were left behind when dug. If potted, perhaps the plant remains root bound with circling roots from being containerized. One remedy is slicing down vertically in 2 or 3 spots at the perimeter of what was the pot to cut through the circling roots. New roots created will grow out normally. Drought conditions can also cause early fall color. Be sure moisture is available. Multi stemmed shrubs/trees can take 2-3 years to recover. If a single stemmed tree, about a year for every inch of trunk diameter.