Thanks to the confusion of Common Names, Snowball Bush is used to describe plants from both the Hydrangea and Viburnum Genera. Hydrangea paniculata 'Grandiflora' or PeeGee(P.G.) is sometimes called Snowball Bush, but the most common reference to Snowball Bush is to Viburnum species from China (V. macrocephalum), Japan (V. plicatum) and Europe (V. opulus).
If they bloom in the spring, they are Viburnum, since the PeeGee (P.G.) Hydrangea blooms later in summer, July-August.
It is interesting to note that most gardeners, some with many years experience, cannot distinguish between the Viburnum & Hydrangea flowers (absent foliage). About the only true distinguishing feature is the number of stamen in each floret, 5 in Viburnum, 7-8+ in Hydrangea.

Here is a link that might be useful: Snowball Bush

That was very interesting!

This is my viburnum opulus (commonly called a snowball bush). It blooms in spring right after the lilacs. Lovely but it can't hold a candle to Annebelle for length of bloom or size of bloom.

Wow, the picture above looks so very much like H.quercifolia 'Harmony'. If the leaves were a bit larger it would be a dead ringer!..Very interesting. Thanks....yg

So i bought some snowballs at a big box store. I have wanted to plant Hydrangea's for some time and they caught my eye. They were not labeed and after calling the company i found out they are Snowball. Do you think that I would be happier in the long run if i bought the Annebelle instead? I live in Loas angeles. Thanks