The Collaborative International Dictionary of English v.0.48:

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. Guelph