The Collaborative International Dictionary
snowball tree
Guelderrose' \Guel"der*rose'\, n. [Supposed to be brought from Guelderland; hence, D. Geldersche roos, G. Gelderische rose, F. rose de Gueldre, It. rose di Gueldra, Sp. rosa de Gueldres.] (Bot.) A cultivated variety of a species of Viburnum ( V. Opulus), bearing large bunches of white flowers; -- called also snowball tree.
Wiktionary
snowball tree
n. guelder rose