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| Fragrance
is determined by the concentration of chemicals in the petals of the flower,
and how these chemicals interact with each other and the atmosphere. Oils,
resins, alcohol's, fatty acids, and phenols all contribute to the character
of the scent. As a general rule, darker colored roses are more fragrant
than white or yellow roses.
Environmental factors which determine how a rose smells on a specific day include climactic conditions such as temperature, humidity, and time of day. Warm, sunny days with low humidity will bring out the best rose fragrance in the garden. Interestingly enough, and somewhat disappointing to us all, the genes responsible for fragrance may also lead to some weakness in disease resistance and how well a rose's blooms hold their petals. One of my favorite David Austin roses, Heritage, smells delightful, with its only shortcoming from what I can ascertain is that its blooms are quite fragile. Nonetheless, Heritage must be in my garden. It should be noted that the comments above are generalizations; there are disease resistant fragrant roses, even in the white and yellow shades. Today's breeders are working hard to develop roses which combine characteristics such as fragrance and disease resistance, and those of us who grow roses should realize that these breeders are striving to overcome significant genetic issues. |