Winterthur, Delaware, February 2016. Photo taken by Mark Detwiler, a fellow traveler in these natural realms.
Below a partial view of flowering plants at Winterthur in late April and very early May 2018.
Spirea

Bridal wreath spirea below flowers of a Wilson pearlbush
Spirea with lilac
Korean Spice Viburnum, fragrant

A Korean spice viburnum hidden from the pathway by evergreens which it envelops with fragrance
The immature flower of the Chinese snowball viburnum (Viburnum Macrocephalum ‘Sterile’) which, in my memory, also turns white
The flower of a Fragrant Snowball (Viburnum X. Carlcephalum)
Saucer Magnolia (Magnolia Soulangiana)

A saucer magnolia framed by a Norway spruce
Wilson Pearlbush (Exochorda Gilbertii, Rosaceae)
Kerria Japonica cultivar, Rosaceae
Flowering Almond (Prunus Triloba, Rosaceae)
Fothergilla (Fothergilla Gardenii), native, fragrant and without petals
On croit sentir les parfums