2005 ARS Award of Merit Certificate Winner
Fragrance in Minis & Mini-Floras
by Mary Peterson
“What’s in a name? That which we call a rose by any other name would smell as sweet.”
-William Shakespeare, Romeo and Juliet
To begin a discussion of fragrance there are a few basics that should be addressed. Whether or not you smell a particular fragrance in a rose depends in some measure on your own personal olfactory system and how sensitive it is.
The Eco-culture in which you grow your roses is also responsible in a large degree to the amount of fragrance produced by them. There are also some additional factors regarding fragrance that should be taken into account.
The amount of sunshine, duration and intensity is an important factor. Temperature, humidity and wind conditions also affect the development of scent. Another aspect to fragrance is that it is affected by disease. Mildew, will cause a loss of scent in roses.
Whether a rose produces a fragrance is due in large part to its genetic ability to produce fragrance. Fragrance is produced by certain glands, petals or leaves. Chemically speaking, we identify certain fragrances produced by aromatic alcohol, aldehyde, fatty acids, phenol, carbonic acid, essential oils and resins.
Since the gene for fragrance is recessive, unless both parents have the gene, you may find the off-spring to be only slightly fragrant or have no fragrance at all. A cross of two fragrant varieties could be expected to produce a preponderance of fragrant seedlings; possibly all of them would be unless the two parents were chosen with widely different types of fragrance.
The genetic background of most miniature roses would seem to limit the number of cultivars that are fragrant due in no small part to most ancestry being traced back to the completely scentless ‘Rouletii’.
The ingredients of perfume are found in the chloroplasts. They are surrounded with glucose which causes them to create the scentless glucosides which are stored or carried in the petals. The scent becomes noticeable if the glucoside is hydrolyzed by an enzyme. The production of a floral scent is a very complex chemical reaction that is influenced by various external influences.
The chemistry of rose fragrance is a complicated mixture of essentials oils. Most importantly is Rhodinol which has the fragrance of ‘old roses’. Another familiar scent is geranium that is produced by Geraniol. Nerol brings the fragrance of magnolias. In orange and yellow roses, Eugenol imparts a spicy fragrance often found in oil of cloves.
Quite possibly the most important factor next to sunshine, soil, and water pH is the amount of moisture available to the plant. When the soil is moist, the roses smell their sweetest because the scent ingredient in the chloroplast increases proportionately and is conveyed to the petals in larger quantities.
As early as the 13th century, rosarians have been intrigued by the possibility of breeding fragrance into their roses. As a rule, darker colored roses are more likely to be highly scented than those lighter shades. The exception is when a flower has more petals; the stronger the scent is likely to be. Heavy petals with a velvety sheen are also more fragrant. The scent comes from tiny cells on the underside of the petals seen with the aid of a microscope.
Not surprisingly there is a definite connection between color and scent. Red and pink roses tend to give off the typical rose scent while the scent from yellow and white roses often is identified as orris, nasturtium, violet or lemon. Orange shades are frequently associated with the odor of fruit. On overcast days, scent is reduced and when the weather is both cold and overcast, it is usually hard to detect any fragrance.
When miniatures were first introduced, the main thrust of the hybridizing effort was to produce small roses with unique color and fragrance really wasn’t a major consideration. ‘Cinderella’ was one of the first miniatures that exhibited fragrance that it inherited from its parent, ‘Cecile Brunner’, but she has been very stingy in passing this trait on to any of her progeny.
One breeder, Ralph Moore, introduced in 1975, a mossy miniature rose, ‘Dresden Doll’ that rewarded him with the fragrance that he had been searching for.
In 1985 Moore introduced a rose with an open rosette form and purplish color that he named ‘Sweet Chariot’. This was another scented triumph that carried the genetic makeup to produce an old rose fragrance.
Many of today’s fragrant miniatures come in shades of lavender or purple. Japan introduced ‘Lavender Crystal’ in 1985. Its unique coloration, full rosette form and penetrating fragrance will endear it to rosarians.
In 1986 Betty Jacobs of Four Seasons Rose Nursery introduced a mini with pointed buds, an elegant high center and long stems. ‘Winter Magic’ (Rise’ n’ Shine x Blue Nile) soon found its way onto the Court of Honor at many rose shows. The foliage is glossy which imparts a certain degree of resistance to fungal diseases. Moore introduced ‘Café Ole’ in 1990 which was a sport of ‘Winter Magic’ and while the coloration was an odd, brownish parchment color that faded to a creamy gray, it also carried the same intense fragrance as its parent. In 1994 Moore crossed the color barrier and introduced ‘Apricot Twist’ a soft apricot with long, pointed buds and a long lasting flower.
In 1985, Nor’ East, under the direction of Harm Saville, picked up the banner and accepted the challenge of introducing a miniature rose with exceptional fragrance. They called their first introduction, ‘Sachet’ a mauve that had a lovely Damask fragrance. ‘Sunny Day’ a deep yellow would follow in 1986. In 1995 they began their fragrance series with the introduction of ‘Scentsational’ a mauve, rosette form mini. This would be the foundation for the fragrance dynasty for Nor’ East. 1996 saw the introduction of ‘Seattle Scentsation’ and in 1998, ‘Overnight Scentsation’ (MF) demanded world-wide media attention when it was taken on board the Space shuttle Columbia STS-95 that included Senator John Glenn. Experiments were carried out in zero gravity to further study how plants create fragrances. Nor’ East continues to introduce fragrant minis and mini-floras in a fascinating color range from white to apricot to medium yellow to deep yellows. In 2002 a fragrant apricot Mini-Flora, ‘Peach Delight’ was introduced and in 2003 they introduced a medium red HT formed mini they named ‘Red Scentsation’. 2004 saw the introduction of ‘Norwich Sweetheart’ which is very fragrant and has a magenta flower with classic HT form.
There are nearly 25 different scents that can be identified in roses, so the next time you enjoy your roses, I hope that you will remember some of the considerations that went into the breeding of a particularly fragrant rose and enjoy that extra bonus in your roses called fragrance.
