CLEOPATRA welcomed Mark Antony in a room knee-deep with rose petals. Shakespeare wrote about the Eglantine rose with apple-scented leaves. Victorian women sniffed their violets and nosegays to mask the odors of the street.
Plenty of aromatic plants never went away, including, from left to right: polyantha primrose; butterfly bush (buddleia), with suggestions of baby powder; saucer magnolia (Magnolia X. soulangiana); Carolina sweetshrub (Calycanthus floridus), suggesting oak barrels to some; clove-scented garden pinks (dianthus); antique rose Petite de Hollande; Oriental lily hybrid and evening-scented petunia Lilac Wave.
Scent may be the most heady garden element of all, but many of our best-loved flowers have lost their fragrance over the last half-century as hybridizers pursued traits like brighter colors, bigger flowers, compact growth or long stems for cutting. Take a whiff of some hybrid red roses, for example, and you'll smell - well, almost nothing: an olfactory blank.
"In cut flower breeding today, the concentration is still on shipability and vase life, and these new flowers have all the romance of an artichoke," said Tom Carruth, research director of Weeks Roses, a wholesale grower based in Upland, Calif.
But as the gardening community grows more sophisticated, and therefore more appreciative of the sensual and the subtle, smell - the final frontier of the senses - is returning to garden fashion.
More nursery catalogs have begun to include lists of fragrant plants on equal footing with categories like hardy vines and ground covers, and breeders are starting to take notice.
In the fall Weeks Roses will introduce a rose named after Julia Child (it has a licorice candy smell) and a purple and lavender rose called Wild Blue Yonder, which has a strong spicy fragrance. Mrs. Child, who died in August, picked her namesake from a sampling of new hybrids.
In addition, the company says old-fashioned varieties that never lost their scent, like Sombreuil, a white climber from the late 19th century, are enjoying a resurgence.
"People go for the color first," Mr. Carruth said by way of explanation. "Then 99.44 percent of the time, it's to the nose."
I'm surprised by how many fragrant flowers are still not promoted, and by how many old or overlooked varieties have yet to make a well-deserved comeback, including native azaleas, bearded iris, clethra and the old-fashioned mock orange.
Fragrance seems to be what gardeners want to talk about this season. On Saturday the Parrish Art Museum, in Southampton, N.Y., will convene a two-day event on scent and the garden, with talks by Stephen Lacey, a British garden columnist and author of "Scent in Your Garden" (Frances Lincoln, 1991), and Robin Clery, a so-called perfume hunter, who captures botanical fragrances for perfume and other products on tropical expeditions.
"Out here the mentality is, if it's bigger, it's better," said Perry Guillot, a landscape architect based in Southampton who helped stage the event. "Fragrance brings gardeners back to simple earthly delights. It's not just about who can buy the biggest tree. Fragrance is so much subtler. It can be a freshly mowed lawn or a honeysuckle that grew in from a neighbor's fence."
By most accounts, humans can detect only five flavors: sweet, sour, bitter, salty and a fifth flavor, derived from the amino acid glutamate and known to the Japanese as umami. But we can discern some 10,000 distinct smells. Without smell, flavors would be barely detectable. Remember holding your nose when you took medicine as a child?
Scents may be plentiful, but they are hard to analyze, and even harder to describe. That may account for why smell is often an afterthought in plant descriptions and garden plans.
Scent is invisible, but its placement is crucial. I wouldn't make a planting themed on fragrance, for example, as I would for spring color or dwarf evergreens. I prefer to sprinkle the smells like punctuation. The lily is an exclamation point; the scent of Carolina sweetshrub floats on the evening air like a question mark: "What's that smell?"
Unfortunately, it's not always easy to find those punctuation marks. After World War II, scent was bred out of roses, for example, as hybridizers worked toward new colors, long stems and durability. Since thick leathery petals do not readily disintegrate, their molecules do not waft into the air. Instead, they remain imbedded and undetectable until the blossom begins to rot.
