Scents

Why and how flowers smell

  • It's not your imagination: most commercial roses smell less. Lavender-colored roses are the exception for now. The lack of smell in roses is the outcome of a push for long-lasting, brightly colored roses.
  • One of the reasons roses are smelling less sweet is that breeders are focused on 26 traits, none of them smell. According to breeder John Dolan, "roses per bush, vase life, color, form, thorns" are all more important commercial characteristics.
  • Since making scent demands a lot of metabolic energy from a flower, long-lasting flowers might be taking energy away from their scent making.
  • Flowers smells are plant survival traits. Terpenes, the chemical compounds that make basil and juniper smell the way they do, discourage herbivores from eating the stems of the plants, while attracting pollinators to their flowers. Citrusy limonene is the terpene that gives lavender its scent. It's also an antibacterial agent.
  • If you want flowers that smell, you're better off sticking to growing your own blooms.
  • Snapdragons have very simple smell mechanisms--only three components contribute to their scent, just compare that to an orchid's one hundred components.
  • The way each flower in a variety has its own smell is by changing the proportion of its odor components, thought the number of components will be shared by the variety.
  • The compound indol in strong concentration smells like sewage, but its low concentration is "a key component of jasmine." Many of the worst smells we experience as humans can be pleasant in very low concentrations.
  • The way a flower smells changes over its lifespan-scents are produced and then fade at different rates over the days the flower is blooming.
  • University professors are trying to isolate the genes that contribute to flowers smelling like flowers, so flower growers can reintroduce the genes, there's also the possibility that they will give scent to odorless blooms, or offer the possibility of new smells for familiar flowers.

Written and researched by Sylvie Beauvais, Philadelphia, PA Adapted from Jonathan Knight, "Aroma therapy." New Scientist, February 12, 2000.