“Scent is the oxidation of essential oils of flowers and leaves. The most intensely scented flowers, lily of-the-valley, orange blossoms, gardenia, Stephanotis floribunda, and tuberose, for example, have thick, velvet-like petals that retain their fragrance by preventing the essential oils from evaporating.
The greater the amount of essential oil produced, the lesser degree of pigmentation in a flower. The oil is the result of the transformation of chlorophyll into tannoid compounds (or pigments), which is in inverseratio to the amount of pigment in a flower. Plants with blue, orange, and red flowers have a high degree of pigmentation and usually generate little or no scent. Pure white flowers release the strongest perfume, followed by creamy white, pale pink, pale yellow, yellow, purple-pink and purple. As color pigment is hybridized and intensified in flowers, fragrance is usually lost or compromised.” –Oh Garden of Fresh Possibilities!