there are some white crabapples, and one called Snowdrift that looks similar. Are the buds pink? Are there small fruits that look like little apples in the fall?
A close up of the flowers and foliage would be helpful.
Another flowering tree with smaller flowers is the flowering pear. Although I think of them as being more pyramidal in shape, a Google search showed more rounded forms. Pears have also thrown out some undersized fruit.
I' guessing from the picture that the flowers are indeed small. If they are larger.. 2" or so and has only four petals, it's a dogwood.
