http://www.durgan.org/URL/?Snowball 24 May 2009 European Snowball (Viburnum opulus) Viburnum opulus 'Roseum' Hardy to zone 3 Also known as European Snowball. The large spherical flowers open apple green and then turn white. There are two bushes on my property. It is a rather spectacular bloomer for about three weeks in late Spring. My plants don't have much fragrance, but some types are most pleasing.