A small tree with pretty white flowers borne in profusion is the Japanese Tree Lilac, Syringa reticulata.
It's hardy in zones 3 to 7, and at maturity it will be 20-30 feet tall and 15-25 feet wide. It has an upright and oval shape, but it becomes more rounded as it grows taller.
In early June this tree lilac is covered in white flower panicles reminiscent of old-fashioned lilac blossoms, though the fragrance is not nearly as pleasant, unfortunately.
However, the flowers and bark are sufficiently ornamental, and that it makes an excellent specimen tree. It is also adaptable and persists in difficult sites, so it's useful as a street tree, which is a bonus indeed!
It enjoys full sun and well-drained soil but adapts well to a range of conditions. Prune it only after it has flowered.
There is no fall color, but it is resistant to serious insect infestations, though it has a tendency to occasionally experience powdery mildew in humid climates.
‘Summer Snow' is a heavy bloomer, and ‘Ivory Silk' starts to flower early on in life so is an excellent choice. Scott Zanon also recommends ‘Regent', which is upright and vigorous, he says, for Midwest gardens.
Reference: Landscaping with Trees in the Midwest by Scott Zanon.
