Winterthur Winterhazel. A hybrid of unknown parentage, this Winterhazel is a selection from the DuPont's Winterthur Gardens in Delaware. Fragrant yellow flowers in April hang in 2" long racemes and cover this 5 to 6 foot tall by 10 foot wide shrub. Great selection for the woodland garden with its natural spreading form. Once one plants a Corylopsis, you will always be gravitating to this plant in late winter when it emerges in flower when most trees are still naked. It has a soft yellow fall color.