Amelanchier canadensis 'Downy Serviceberry': Has wonderful blossoms followed by blueberry-like fruit in June. 

Will eventually grow 15' to 20', but can be kept smaller  to fit the area it is growing in.  Tends to be multi-limbed and shrub-like, but can be trained to one trunk. Fall color is wonderful! 

This small tree is well worth growing. 

Can be grown in partial sun, but for fruit production and fall color, full sun is needed.  Not too fussy as to soil conditions and is hardy to zone 4.