In 1962 an interviewer asked Henry Francis du Pont (1880-1969) to discuss the defining aesthetic principles of his great naturalistic garden at Winterthur. Du Pont replied, “For me, color is the thing that counts more than any other.”
The following is a list of the major plant groupings at Winterthur, listing the flower colors and time of bloom in Delaware (Zone 6B). For more than 65 years H. F. du Pont observed succession of bloom, experimenting with thousands of plants and refining the color combinations that are the essence of the Winterthur Garden.
| Color | Time of Bloom | |
| March Bank | ||
| Galanthus spp. (Snowdrops) | White | January-March |
| Adonis amurensis (Amur Adonis) | Yellow | March |
| Eranthis hyemalis (Winter Aconite) | Yellow | March |
| Chionodoxa spp. (Glory-of-the-Snow) | Blue | March |
| Scilla spp. (Squills) | Blue | March |
| Leucojum vernum (Spring Snowflake) | White | March |
| Crocus spp. and hybrids | Various | March |
| Cornus officinalis (Cornelian-Cherry) | Yellow | March |
| Narcissus spp. and cv. (Daffodils, early) | Yellow | March, April |
| Uvularia grandiflora (Bellwort) | Yellow | April |
| Mertensia virginica (Virginia Bluebell) | Blue | April, May |
| Phlox divaricata (Wild Phlox) | Lavender | April, May |
| Hosta ventricosa | Lavender | July |
| Winterhazel Walk | ||
| Corylopsis spp. (Winterhazel) | Yellow | April |
| Rhododendron mucronulatum (Korean R.) | Lavender | April |
| Helleborus spp. (Hellebores) | Various | April |
| Corydalis bulbosa | Lavender | April |
| Primula abchasica (Abkhazian Primrose) | Pink | April |
| Pinetum | ||
| Chaenomeles spp. and cvs. (Flowering Quince) | Various | April |
| Viburnum spp. | Chartreuse, white | April, May |
| Spiraea spp. | White | April |
| Rhododendron spp. and cvs.(Deciduous Azaleas) | Pink, Yellow, Orange | April, May |
| Rhododendron cvs.(Kurume Hybrid Azaleas) | Pinks | May |
| Sundial Garden | ||
| Magnolia spp. and cvs. | White, pink | April |
| Spiraea spp. | White | April |
| Chaenomeles spp. and cvs. (Flowering Quince) | Pink, red | April |
| Prunus spp. and cvs. (Cherries) | Pink | April |
| Viburnum spp. and cvs. | White | April |
| Fothergilla spp. and cvs. | White | April, May |
| Malus cvs. (Crabapples) | Pink | April |
| Exochorda spp. and cvs. (Pearlbushes) | White | April, May |
| Syringa cvs. (Lilacs) | Lavenders, white | May |
| Paulownia tomentosa (Princess Tree) | Lavender | May |
| Azalea Woods | ||
| Anemone apennina (Italian Windflower) | Lavender, white | April |
| Trillium grandiflorum | White | April, May |
| Rhododendron cvs.(Kurume Hybrid Azaleas) | Various | May |
| R. kaempferi (Torch Azalea) | Pinks | May |
| Rhododendron spp. and cvs. | Various | May |
| Hyacinthoides hispanica (Spanish Bluebell) | Blue | May |
| Peony Garden | ||
| Paeonia cvs. (Hybrid tree peonies) | Various | May |
| Paeonia cvs. (Herbaceous peonies) | Various | May |
| Rhododendron cvs. (Kurume Azaleas) | Pink | May |
| Kolkwitzia amabilis (Beautybush) | Pink | May |
| Sycamore Hill | ||
| Narcissus cvs. (Daffodils) | Yellow, white | April |
| Cercis canadensis (Redbud) | Lavender | April, May |
| Syringa spp. and cvs. | Lavender | May |
| Aesculus pavia (Red Buckeye) | Red | May |
| Kalmia latifolia (Mountain-laurel) | Pink | May, June |
| Chionanthus virginicus (Fringe Tree) | White | May, June |
| Deutzia spp. and cvs | White, lavender |