RHA Newsletter 5(3): 2-5 (Fall 1974)
I Breed Miniatures
Ralph S. Moore

Since Miniature Roses are growing in popularity in our rose shows, it seemed appropriate to print an article on hybridizing miniatures. And we are very grateful to Mr. Ralph S. Moore, of Sequoia Nursery, hybridizer of many lovely miniature rose varieties, for granting us permission to reprint his fine article, "I Breed Miniatures" from the 1957 Rose Annual.

by Ralph S. Moore

"For some time I have been asked to put into writing an account of my work with Miniature roses. In the space allotted to me I shall attempt to tell the story of "made in America" Miniatures.

My work goes back some 20 years. At that time the first of these little roses had found their way to America. Rosa Rouletti came first, followed shortly after by Tom Thumb and Oakington Ruby. These latter two kinds were to play an important part in my own future as well as the future of Miniature roses in general.

About this same time some Polyantha seedlings of my own were just reaching the stage of first bloom. In 1938 one of these seedlings (later introduced as Carolyn Dean) was crossed with Tom Thumb. From this lot of seedlings came a plant destined to re-shape the whole future of Miniature roses.

Future Use of Zee

In one package this seedling (since identified in our breeding records under the name Zee) carries more genetic dynamite, as far as Miniatures are concerned, than any other we know of. Good foliage, free bloom, desirable bud form, heavy production of good pollen, compatibility with many varieties — all these — characterize this seedling. However, in itself the flower is insignificant, rather loose in form and pale pink in color. It is used only for breeding and is not in commerce. Hereafter, in mentioning crosses, I shall use the name Zee wherever this variety was used as a parent.

In 1938 or 1939 a sister seedling to Carolyn Dean (introduced later as Dancing Doll) was crossed with Oakington Ruby to produce Cutie (Patent 1302) — really the first "made in America" Miniature.

Then quite a lot of open-pollenated seed of Oakington Ruby was sown to discover what traits were buried in its heredity. From these came Centennial Miss (Patent 1301), Patty Lou (Patent 1335) and Pink Joy (Patent 1378). Later Oakington Ruby was successfully crossed with Floradora to produce a seedling combining traits from both parents — very vigorous upright growth with small dark green foliage and extremely dark red flowers of little value. In certain crosses this too has proven to be a valuable parent. Thus the stage was set for the creation of new and better Miniature roses.

Miniature Defined

To clarify the subject, allow me to set down just what a Miniature rose is, and what it is not. Even though some varieties of Miniatures have been around for many years, it is safe to assume that many gardeners have never ever seen one. First, Miniatures are not Floribundas nor are they Polyantha roses — such as are often bought from the florist as a potted plant. These two classes of roses are known for their much branched, relatively low growing habits and clusters of small to medium-sized flowers. However, the foliage is large, branches rather stiff and the internodes (space between leaves) medium to rather long.

Miniatures have tiny leaves, are much-branched and make thick compact plants. The internodes are very short, thus placing the leaves close together. Buds, flowers, leaves stems, thorns — every part of the plant is much reduced in size as compared to the larger forms of the rose, yet in perfect proportion. Miniatures are not produced by any art of grafting or pruning. They are miniature because of hereditary determiners within the cell called genes.

Miniatures vary from variety to variety in growth habits and other plant characteristics. Bush Miniatures may be expected to grow six to 16 inches high and from six to 18 inches broad at maturity. My Climbing Miniature plants vary from two and one-half (Redhead and Fairy Princess) to five feet (Pink Cameo) in height.

The original Rosa Rouletti resembles some of the old China and Tea roses. A number of the earlier European varieties lacked the modern pointed bud, mainly because this factor was not present in the cross of Tom Thumb or related varieties onto the older short-budded Polyantha roses used as seed parents. In my work, using Zee as the pollen parent, a greater part of the seedlings have the long-budded Hybrid Tea form, only in miniature.

It's Slow Work

My own work with Miniature rose development, beginning about 1936, passed through a slow testing and observation period during which a number of basic crosses were made and breeding materials assembled or developed. This was a learning process which has continued up to the present day. All this was necessary because I was not content to just make a new miniature rose but dreamed of a whole new race of Miniatures.

My mental blueprint for these new Miniatures set forth a number of qualities or goals. I wanted Miniatures in the full color range of the Hybrid Teas. Bud form should resemble that of the best Hybrid Tea. Plants must be hardy, vigorous, easy to grow and easy to propagate. I wanted compact, well-rounded plants with good foliage and heavy flower production. But this was, and is, a big order which probably will never be fully attained. However, gratifying progress along these lines is being achieved. With such a goal it was necessary to learn as much as possible about Miniatures. So little was known or available about the breeding and patterns of inheritance of Miniatures that it was only by theory and the trial and error method that I was able to progress. By crossing, inter-crossing and back crossing many varieties, types, unnamed seedlings and even several wild species, bits of knowledge were gradually assembled, theories proved or disproved and the all important know-how emerged.

Most Miniatures produce little or no pollen, and if you have ever carefully examined a Miniature rose flower the problem of working with such smallness is apparent. Most seed-producing Miniatures carry but one to three seeds in each hip and often these are not viable. Of course, Lady Luck could be with us, and a good variety could come out of very few seeds, but the odds are against it. It is usually necessary to make many crosses and grow seedlings on a much larger scale.

Other Classes Are Used

Along with my Miniature crosses I continually make new combinations of Hybrid Tea, Floribunda, Polyantha and species roses. These are merely to assemble desirable qualities which I wish later to breed into the newer miniatures. Thus the new Miniatures are becoming more and more complex in their heredity.

As has been stated earlier, certain crosses in the past have produced a few seedlings of exceptional value for breeding, and more recently a few more have shown up. By and large, the best commercial or garden varieties are of little value for breeding.

In working with Miniatures the laws of Mendel also apply. The pattern of inheritance for bush and climber, flower color, foliage, thorns, etc, follows that of the larger roses. However, since it was known that the small flower of the Polyantha and Floribunda was determined by a recessive factor or factors it seemed to most breeders that the Miniature must also fall into this pattern. In my own mind this did not appear to be necessarily true, but it was only after a period of years and the observation of many thousands of seedlings of many heredity combinations that I have proven to my satisfaction that the miniature factor is dominant rather than recessive. (Author's correction: When I say that the miniature factor is dominant — please compare with my later mention in my book "All About Miniature Roses" where I say that the miniature factor (or factors) may behave as dominant but that I now believe such factor(s) to possibly be inhibitors as they seem to be closely related to the fertility/sterility factors.)

It is thus possible, as I have done, to cross larger-flowered roses with Miniatures and produce Miniatures (such as Bit o' Sunshine). Some of these seedlings, having genes for miniature from only one parent when crossed to another rose carrying no miniature genes, have produced miniature, tiny leaved, bushy plants bearing miniature flowers only one-half to one inch in diameter. If this were a recessive factor, both parents would have to carry miniature genes. Thus the facts indicate that the miniature factor is dominant.

Anything is Possible

With these basic facts, or working tools, clearly in mind it is possible to produce almost any kind or color of Miniature rose. In practice it is not so simple. The varieties we wish most to cross may be infertile or incompatible so we have to work with what we have. Sometimes this means several classes, growing many seedlings and then re-combinations. In practice, plants used as seed parents should set seed easily, producing four to 10 good seeds per hip.

 In my own work I most often use Climbers as seed parents. These are often unnamed seedlings produced by crossing a Climber and a bush rose, hence carrying the recessive genes for bush. It is thus possible to make combinations otherwise impossible and to do it in quantity. The one drawback being that only one-forth of the offspring will come bush. This method is especially useful when working with once-blooming species such as R. Multiflora and R. Wichuraiana or other hardy once-blooming Climbers.

While it is possible to produce Miniatures having one-half inch flowers on six-inch plants such as Lemon Drop, these very tiny kinds are limited in their appeal and usefulness. Varieties having one-inch or slightly larger flowers are more showy. Many of the newer kinds such as Frosty, Jackie and Bit o' Sunshine bear flowers about one and one-fourth inches in diameter on sturdy, more easily grown plants. They are hardier and more useful.

New Characteristics Appear

Because of the diversity of material used in my work over the years, new forms and colors as well as new types of plant habit are emerging. I referred earlier to the Climbing Miniatures. The first of these (and one of the best) was Pink Cameo. It has perfect deep pink hybrid Tea-shaped buds, The plant is everblooming, performing well outdoors or under glass. Some of these roses, such as Fairy Princess, have smaller flowers and tiny fern-like foliage. Papoose is a miniature Rosa wichuraiana, useful as a ground cover and bearing single white flowers like strawberry blossoms.

A new break is the Miniature which came out of a cross of the older rambler, Violette X Zee. This variety grows with arching branches (like miniature Multiflora) to a height of three to four feet, spreading to about five feet. Foliage is abundant, fern-like, clean and glossy. Flowers are pink, about three-fourth inch in diameter and very double. Plants bloom heavily in spring and continue to repeat to frost. To be introduced this spring, this variety may be used individually as a shrub or planted as a neat everblooming hedge which may be sheared or left to grow naturally.

The color range is quite good now but we are working to produce more red flowered kinds with brilliant color and shapely buds. Several whites are available, and with the introduction of Bit o' Sunshine we have a bright yellow. Last season's introduction of my Candleflame, a single with streamlined yellow and orange colored buds gave us the first Miniature in the lilac tones but it is slow to propagate. We flow have a new lilac or orchid-shaded seedling under test which looks promising. In the newer seedlings we even have a plant with pale green flowers and another with stripes.

Still another departure in form is the new aster-flowered strain of Miniature, The first of these will be introduced this spring under the name White Aster. It is a (Rosa Wichuraiana X Floradora) X Zee seedling. Flowers are produced in profusion on a compact 10 to 12-inch plant. The beautifully shaped buds are soft pink in cool weather. The open flower is made up of many narrow recurving white petals which give it the appearance of a miniature aster bloom. Others of this type in shades of pink and lavender are under observation.

The successful combination of some of the hardy Brownell sub-zero varieties with my Miniatures has given rise to yet another desirable form of Miniature rose. Of these, three kinds are now available.

Little Buckaroo gives us the first of another breeding line developed from a cross of (Rosa Wichuralana X Floradora X (Oakington Ruby X Floradora). The plant of this variety grows larger than most miniatures but its rich foliage and bright red flowers make it useful for low hedges, and as a Potted plant around the home or garden. For cutting it is long-lasting and easy to arrange. A bright glowing pink of this same cross will soon be available and others will follow.

Here is a complete listing of my miniature rose productions:

Editor's Note: Since this article was published (1957) Mr. Moore has hybridized many more fine Miniature Roses. For further literature on Miniatures it is suggested that you read Mr. Moore's book "All About Miniature Roses" and a new booklet he is having printed now on the subject.