Breeding And Fragrance|
(Also consult the American Rose Society: Fragrance)
The thousands of different roses available today all trace their heritage back to the twelve dozen or so species roses, the ones that grow in the wild. The process of obtaining new roses is called hybridization. In this process, the pollen from one plant fertilizes the ovary of another. The plants from the resulting seeds will all be different.
Bees and other pollinating insects can cause this process to happen "naturally." Man can also create hybrids and has raised it to a fine art in the last hundred-plus years, continually improving both flowers and plants. The overall procedure is lengthy - - from crossing to introduction to the public takes seven to ten years of painstaking work.
Before the cross is made, the hybridizer selects the parent plants, taking into account color, form, hardiness, disease resistance, foliage, and so forth. Next, the outer petals of the selected parents are removed, exposing the reproductive organs. All roses have both male and female parts. In the center of the flower are the female organs - - pistils and bear pollen- producing anthers.
To prevent self-pollination, the anthers are removed on the "mother" plants. The anthers on the "father" plant are harvested, labeled, and stored. About a day later, a sticky substance forms on the stigmas. The anthers release the dust- size pollen at about the same time, at which point it is brushed on the stigmas.
The rose is now labeled with information such as date and parentage. A bag is placed over the pollinated flower, protecting it from any further pollination. If fertilization occurred, the area beneath the reproductive organs begins to swell. This is the hip, or fruit, of the rose. It ripens in several months, is harvested, and the seeds removed.
The seeds are then cleaned and stratified, a process in which the seeds are placed in small containers of peat moss and stored at 400F. for six weeks, before being planted. Growing in a greenhouse, the first flowers may appear within seven to eight weeks after germination, giving an indication of this new plant's potential.
A hybridizer may look over as many as a hundred thousand seedlings each year, with 99 percent discarded at some point during the first growing season. What makes this part of the job even harder than it sounds is that sometimes a promising-looking seedling will not do well when budded onto rootstock and grown outdoors. Conversely, an average-appearing plant may exhibit something special when bud-grafted and grown on.
The seedlings that pass muster are now ready for field testing and evaluation. More than just one plant is needed for this, so the original seedling is propagated. In order to have additional plants exactly like the parent, new ones are started by taking a cutting of a piece of stem that is the bud, or eye, found at the point where the leaf joins the stem. This is grafted onto a rootstock - - a rooted cutting of another rose.
Grafting is necessary because many of today's complex hybrids root poorly or erratically on their own. Most garden roses are grown on a variety of multiflora rose. Buds are taken from dormant plants in late fall and grafted the following spring or summer. (For more information, see the American Rose Society: Propagation)
It is as budded, field-grown plants that these new roses really begin to "show off." More are discarded and a few are budded in larger quantities for further testing. Only about a hundred make it to the second budding.
For at least another two to four years this process continues until only a handful remain. Some of the most promising are entered in the All-America Rose Selections judging. Four plants of each variety are sent to the 23 AARS test gardens around the country for two more years of observation. Once a company is ready to introduce a variety, large quantities of plants are budded and grown to marketable age - - a period of another two.
Long and arduous, the process of hybridization is now complete. The new variety - superior in any number of ways, be it color, fragrance, foliage, hardiness, disease resistance, or whatever - is now ready to bloom and grow beautifully in yards all over the country. Who knows? It may be the best seller, the one topping PEACE with over 20 million plants sold since 1945 and nearly every home rose garden having one!
One rose characteristic which most people expect is fragrance. Watch someone walk by roses in full bloom. First, there'll be an exclamation over color or beauty, but, inevitably, the head will bend in expectation of that special scent we've come to expect.
Many years ago Alice Morse Earle wrote, "The fragrance of the sweetest rose is beyond an other flower scent, it is irresistible, enthralling; you cannot leave it. I have never doubted the rose has some compelling quality not shared by other flowers. I do not know whether it comes from some inherent witchery of the plant, but it certainly exists."
Elusive, mysterious, the fragrance of roses and the romance surrounding it is legendary. For instance, Cleopatra supposedly entertained Marc Anthony in a room filled with 18 inches of rose petals, and the sails of her ship were soaked with rose water so that "the very winds were lovesick." In the 1300's, Queen Elizabeth of Hungary, whose beauty ritual included quantities of rose water, was, at the age of 72, able to successfully woo the King of Poland. At a seventeenth-century Persian royal wedding, rose petals were floated on garden canals filled with rose water. Such lavishness attests to both the literal and figurative power of rose fragrance.
Some of the mystery and illusion of rose fragrance may, in part, be due to the fact that there are actually over two dozen different sorts of rose scent, with some roses having a mixture of these various perfumes. The seven basic scents that are most often found in hybrid tea roses include rose, nasturtium, orris, violet, apple, lemon, and clover. Some of the other scents are fern or moss, hyacinth, orange, bay anise, lily-of-the-valley, linseed oil, hone, wine, marigold, quince, geranium, peppers, parsley, and raspberry.
In general, the most highly scented roses are ones that are either darker in color, have more petals to the flower, or have thick, velvety petals. Another correlation is that the red and pink roses are most likely to smell like a "rose," while white and yellow ones lean to orris, nasturtium,violet, or lemon. Orange-shaded roses will usually have scents of fruit, orris, nasturtium, violet, or clover.
Rose fragrance will be strongest on warm, sunny days when the soil is moist because that is when the production of the scent ingredients increases. Often, a rose that was fragrant in the morning is no longer so by late afternoon. A variety which seems immune to the vagaries of weather is CHRYSLER IMPERIAL and SUTTER'S GOLD are fragrant even on cool, cloudy days. CHRYSLER IMPERIAL as well as MISTER LINCOLN are two of the best roses for potpourri as they also keep their strong scent after drying.
Another interesting aspect to fragrance is that it is affected by disease. Mildew, especially, will cause a loss of scent.
No discussion of roses and fragrance is immune to the argument that the "new" roses just don't have the strong, sweet smell of the "old" roses. Nostalgia withstanding, "it ain't necessarily so."
Dr. W. E. Lammerts, a rose scientist, did an in-depth analysis in 1951 and found that quite a few of the older rose varieties were either only moderately scented or had no scent at all. In 1956, Dr. James A. Gamble reported in the American Rose Annual that on examination of 3,900 rose varieties, both old and new, 25 percent were scentless, 20 percent strongly scented, and the rest had some scent.
To encourage the development of fragrance in roses, Dr. Gamble endowed the American Rose Society with funds so to award hybridizers who produced roses of outstanding fragrance and growth habit. Since 1953, there have been numerous winners. Some are TIFFANY, CHRYSLER IMPERIAL, FRAGRANT CLOUD and DOUBLE DELIGHT.
Besides the roses already mentioned, some other hybrid tea and grandiflora roses with significant fragrance include: ARIZONA, COMMAND PERFORMANCE, ELECTRON, FRIENDSHIP, LOVE, PERFUME DELIGHT, SUNDOWNER, SHEER BLISS, SWEET SURRENDER AND WHITE LIGHTNIN'. Some fragrant floribundas are ANGEL FACE, APRICOT NECTAR, CATHEDRAL, CHERISH, INTRIGUE and SARATOGA, white AMERICA is a climber with a spicy scent.