Luther Burbank: His Methods and Discoveries. Vol. 9: 41-69 (1914)
WORKING WITH A UNIVERSAL FLOWER—THE ROSE
HOW THE BURBANK AND OTHER ROSES WERE PRODUCED

THE most popular of any roses I have so far introduced is undoubtedly the one known as the Burbank.

The popularity of this rose is, I trust, well deserved. But I should not be disposed to admit that its merits are greater than those of many of my newer roses which have not yet made their appearance in public. The popularity of the Burbank is partly to be explained by the fact that it has been a good while before the public.

There is a time element in the introduction of a new flower, just as in the introduction of a new fruit. In fact, no new plant development could be expected to make its way except very gradually at first, although it gains momentum rapidly after a time. In this regard, the introduction of a flower is analogous to the development of the flower itself through successive generations of variation.

We have seen that when any given variation is in question, there is a tendency to much more rapid change after the experiment has progressed a certain number of stages.

Similarly a flower or fruit that the public at first accepts rather grudgingly may at last become so popular that it is impossible to produce it rapidly enough to meet the demand.


An Attractive Chilean Rose Bush
Mr. Burbank has gathered roses from all over the world, and used them in all manner of breeding experiments, both in the way of pure selection and of hybridization. Here is a highly attractive variety that came from Chile. It is but one of many hundreds, yet it has distinction in any company.

The Burbank rose, to be sure, did not fail of recognition from the outset. But its gaining of the gold medal as the best bedding rose at the St. Louis International Exposition in 1904 was doubtless the thing that advertised it most extensively, and led to its rather exceptionally rapid acceptance by the public.

On my own part, I look with particular pride on this rose, not so much because it received the gold medal as because competent judges everywhere have admitted that it deserved the recognition thus given it as the best bedding rose.

I have produced many plant developments that are much more spectacular than the new rose, and many that have elements of far greater novelty and interest from the standpoint of both plant developer and the general public. Yet I may be permitted to indulge in a rather exceptional satisfaction over the success of this flower for the reason that the rose is probably the most popular of all cultivated plants, and the one that has received most attention from horticulturists of all classes, professional and amateur alike.

In attempting to introduce a new rose, then, the plant developer is coming in competition with a vast number of workers, and the product with which he operates is to be measured against an almost bewildering number of similar products that have attained a high degree of improvement. So, as I said, the plant developer may sometimes regard with greater satisfaction such an accomplishment as this, than a more spectacular achievement in plant development in a line where there is no competition.

HOW THE BURBANK WAS PRODUCED

The origin of the Burbank rose suggests in a way the origin of that very different plant development, the Burbank potato.

I was not personally responsible for either name, and the analogy between the manner of production of the rose and the potato was doubtless not at all in the mind of the dealer who christened the new flower. Still, as I have just intimated, there is a certain added propriety in the use of my name in connection with this particular rose as against a good many other roses that I have developed, because of the fact that the manner of its production suggested that of the production of the first of my important plant developments. In a word, the Burbank rose, like the Burbank potato, owes its origin to the discovery of a seed-pod on a plant that rarely produces seed.

The plant in the present instance was a Bourbon rose, of the familiar and typical species known as Hermosa. This rose very rarely bears seed, even in California, but on one occasion I discovered half a dozen seed-pods on a plant that did not differ otherwise in any obvious way from its companion plants.


Roses at Sebastopol
Mr. Burbank's chief rose colonies are on his farm at Sebastopol, seven miles from Santa Rosa; on the same acreage with the fruit orchards described and depicted in other volumes, and with numberless flowers to be shown in the present volume. This picture gives a characteristic glimpse of the rose colony in blossoming time.

A Mammoth Bouquet
A number of rose bushes have grown together, to form a mammoth cluster. Of all the interesting and spectacular flower exhibits in Mr. Burbank's garden, few are more popular than the various masses of roses of many varieties.

Another View of the Proving Ground
Here we see another corner of the Sebastopol rose colony. The flowers here are not massed for display, but are disposed in rows for convenience of observation. As seen here, they represent transition stages; and a glance shows that they have great possibilities.

I carefully treasured these seeds, and from the plants that they grew are descended not only the Burbank rose, but also the Santa Rosa, and a number of others that are less well known.

With the fact that the Burbank rose was a product of seeds thus accidentally garnered, however, the analogy with the Burbank potato ceases.

For, whereas the tuberous vegetable was produced in full perfection on one of the plants grown directly from the seeds found in the potato ball, the Burbank rose was developed only after numerous hybridizing experiments in which new blood was introduced, and new qualities were brought into the combination.

Among other roses, the strains of which were mingled with those of the offspring of the Hermosa to produce the Burbank, was the Bon Silene. And there were at least three or four others that are similarly to be credited, although the exact pedigrees of all of them are not matter of record.

Still the initial impulse to variation which supplied the material for the new hybridizings, and was thus primarily responsible for the outcome, was given by the seeds gathered from the Hermosa. The same tendency to increased vigor and productivity and variation that we saw manifested in the case of the potato, and to which reference has been made also in the case of the sugar-cane, and of other plants that are usually propagated by division rather than by cross-fertilization, was doubtless given the seeds of the rose by a chance mingling of just the right kind of pollen—brought by some vagrant bee—with its usually unreceptive ovules.

The lesson that cross-fertilization gives vigor, and provides the materials for variation, which we have seen emphasized so many times, is here given a fresh illustration. It is a lesson that the grower of roses and other long-cultivated flowers may well bear in mind.

When the resources of selection have been practically exhausted, and a particular variety of flower has reached a static period, in which it seems to present no further opportunity for development in a given direction—say as to its odor, or its color, or its size—the plant experimenter should never forget that there still lies open to him the possibility of introducing new elements of variability, and new opportunities for improvement, through hybridization.

This, of course, assumes that the flower has not been so specialized that all its stamens have been transformed into petals, so that it becomes absolutely fertile [sic]. Such a transformation has, indeed, been effected with a good many of the cultivated flowers, including some of the roses. And the case of the Hermosa, just cited, illustrates the fact that some of our roses are practically sterile. Indeed most of them are so.

But then the flower that has ceased to have productive stamens may sometimes still have a receptive pistil, so that new blood may be introduced from a species that retains normal virility although in general, such flowers show small capacity even for accepting the pollen.

CHARACTERISTICS OF THE NEW ROSES

The new Burbank rose and its sister plant, the Santa Rosa, present further object lessons in the value of cross-fertilization, in that they are not only much more beautiful than the original Hermosa from which they sprang, but that they also have qualities of hardiness and of productivity that are the token of their mixed heritage.

The new races are, indeed, so hardy that they thrive in the northernmost parts of the United States and in southern Canada. They are the hardiest of all everblooming roses.

Their vigor and capacity for production of flowers are so great that they bloom incessantly throughout the season. Among all the roses there is none that excels them in the matter of almost perpetual blooming. The number of flowers produced by an individual plant is also quite out of the ordinary.

Meantime the flowers themselves are very superior in color to those of the Hermosa, and the foliage of the plants is glossy and brilliant.

These qualities were of course taken into consideration by the judges who gave the gold medal to the Burbank. But there were others which were given, no doubt, almost equal attention by the experts. One of these is the vigorous habit of growth of the plant, through which it comes about that it may be propagated almost as readily as the least fragrant weed; will root almost as easily as blue-grass, and will bloom when only two or three inches in height, and keep n blooming month after month, and year after year, if the buds are not actually frozen.

Another exceptional quality, which some practical horticulturists might regard as constituting a merit surpassing all the rest, is the power of resistance of the Burbank rose—which the Santa Rosa shares—to those ever-present foes of the rose family, mildew and rust.

The new roses appear to be absolutely immune to the attacks not alone of these, but of other fungoid enemies.

Their healthiness under all climatic conditions is their final and definitive quality.

MAKING PLANTS IMMUNE TO DISEASE


Unnamed Beauties
Here are roses in profusion, of many varieties, all new, and as yet all nameless. It would be futile to suggest how many new varieties of roses there may be, all told, in Mr. Burbank's colony at Sebastopol. Any number of these new varieties have exceptional beauty; but only here and there one will be preserved for further experiments, and rarer still are the ones that will have the honor of introduction.

This quality of immunity to disease, while primarily due, no doubt, to the enhanced vitality given the flowers through hybridization, has been accentuated and developed by persistent selection.

In this regard, the roses do not differ from practically all other plants with which I operate. I have referred more than once to my method of developing immune races of plants and emphasize it once more with propriety in the present connection, because, as is well known, the rose is peculiarly susceptible to the attacks of many fungoid and insect enemies.

Indeed, many a rose that would otherwise have value is so susceptible to the attacks of disease that it not only gives no pleasure to its owner, but becomes a source of infection in the garden that makes its presence a menace to other flowers.

To give plants immunity to the chief diseases to which their species is subject is, therefore, one of the prominent aims that I never overlook in the course of experiments, no matter what the particular quality that may be chiefly sought.

Therefore I make it the invariable rule, whatsoever the plant with which I am working, to examine the seedlings attentively from time to time, to note whether any of them give evidence of infection by mildew or any fungous growth.


The Santa Rosa Rose
This is a variety that, singled out among thousands, was thought worthy of introduction. Moreover it was exceptionally honored in being given the name Santa Rosa. Mr. Burbank must have thought it nearly perfect of its kind, or he would not thus have honored it. The color photograph testifies that his confidence was justified.

And any seedling that is seen to be subject to mildew is at once destroyed, regardless of the value of its other qualities.

I should not regard a plant experiment successful that led to the production of the most beautiful and most fragrant and most prolific of roses, if at the same time the plant that exhibited these qualities was susceptible to mildew. Indeed, I have destroyed thousands of otherwise promising roses for the simple reason that they were subject to mildew.

I have obtained scores of climbing roses that were worthy to compete with the Crimson Rambler or the Philadelphia Rambler and other standard varieties, yet which have not been allowed to live because of their susceptibility to disease.

But the reward of this unflinching application of a principle has resulted in various types of roses that are quite generally mildew-proof.

Among the ramblers just referred to, for example, by sedulous application of the principles of selection, preserving only those plants that showed themselves to have the quality of inherent resistance to the fungus, I have remaining, after thousands of their fellows have fallen by the wayside, a few rambler roses of wholly new types, which are immune to disease. This selection is not as difficult as might be supposed, because a rose that is intensely susceptible is generally attacked during the first one or two years of its existence.

Moreover, these new mildew-proof ramblers manifest, partly perhaps as an evidence of the vitality that makes them immune to disease, a capacity to produce enormous clusters of the most beautiful flowers that approach the keeping qualities of some of the everlastings.

Some of them will last at least a month, on the plant or when cut, showing thus a degree of permanency hitherto quite unheard of among roses.

ORIGIN OF THE ROBUST RAMBLERS


A New Yellow Rambler
The ramblers, of many types, are favorites with Mr. Burbank. He has crossbred any number of them, and has produced some very notable new varieties. Here is a yellow one that has obvious distinction. As yet it has no name.

These hardy and prolific new ramblers are largely hybrids.

There are several varieties of them representing different crosses between the well-known Crimson Rambler and such roses as the Empress of India and the Cecil Bruner and dozens of others.

Those of the first named cross often have enormous stems, with deep red hairy branches; while the hybrids of other crosses often have slender, smooth branches.

But the hybrids themselves have been interbred, and other strains that seem to give good promise were brought into their heredity, so that they have traits that do not belong to any of the original parents.

Some of these new ramblers have very large, broad crimson prickles; others have long slender ones set very closely together; still others are quite without prickles, being as smooth as the Banksias.

In color, the new ramblers vary through crimson, scarlet, and pink to snowy white. Moreover, some of them resemble the Japanese primrose in color, and, when trained on a wall, present such a unique appearance that they would not be recognized as roses when viewed from a little distance. These in particular are especially long keepers.

In explanation of what has just been said as to the uncertainties of the precise lineage of some of my roses, it may be added I have experimented first and last with a very large number of species and varieties of both commonly cultivated and wild ones, and I have not found it expedient or of any special significance to attempt to keep a precise record of the hybridizations after they become very complex.

For a good many years, to be sure, I kept accurate check on the various crosses.

The names of the parents used in an original hybridizing experiment were always recorded.

Later, as the cross became more complex, large numbers of species being utilized, I attempted short cuts by using numbers and letters on my labels, the key to these being recorded in my plan books.

This worked very well for a few years more. But there came a time when an experiment with a single strain of roses had been carried through so many generations that the traits of ten species or more would be combined in an individual.

At this stage I abandoned the numbers and letters, and contented myself with a general knowledge of the principal ancestors in the pedigree of any new variety, distinguishing the new variety itself by a temporary name for purposes of further record.

Thus I have, for example, grown upward of two hundred thousand seedlings from the Crimson Rambler pollenated with all the ordinary roses that are under cultivation in California. The pollen of only a few of them proved effective. But here and there a rose like the Empress of India or the Cecil Bruner will hybridize readily with the Rambler. Then it is possible to cross the hybrids with numerous other hybridized roses, some of which would not cross, or cross very unwillingly, with the Crimson Rambler itself.

The parents for the new crosses being themselves hybrids of complicated ancestry, it is obvious that the pedigrees in a few generations become so complicated that if one were to attempt to trace them there would be little time left for any other experiments.

So, as I said, I have contented myself with watching for results among the hybrid progeny of my roses of multiple ancestry.

There are a few of the new developments that carry strains of almost every rose generally known and cultivated up to within ten years ago, and many species not under cultivation.

SOME ANCESTORS OF THE NEW ROSES


The Corona Rose
This is a crimson rambler seedling, of mixed heritage, that has altogether notable qualities as to justify its introduction. It is named the Corona. Like many of Mr. Burbank's selected ramblers, it is extraordinarily vigorous, thrifty, and prolific.

It would be superfluous to name all the species that I have had under cultivation and have tested as to their possible value as hybridizing agents.

Even were I disposed to make such a record, it would necessarily lack finality. For there are perhaps few plants regarding which botanists are more at variance, when it comes to the matter of classifying and differentiating the species.

It is recorded, for example, that some classifiers estimate the total number of species of roses at about thirty; whereas, on the other hand, a French botanist of some authority has described no fewer than 4,266 species from Europe and Western Asia alone. Meantime, botanists in general are disposed to recognize something over 100 species, not always being able to agree as to which forms are entitled to rank only as varieties.

If there is such uncertainty among the professional classifiers, it goes without saying that the vagueness of characterization of different alleged species and varieties is far greater among practical horticulturists. There are, to be sure, a good many pretty clearly fixed types that are everywhere recognized as having individuality. But each of these is represented by many varieties, and these varieties tend more or less to run into one another. This can hardly be otherwise, considering the extent to which hybridization takes place.

So, as I said, it would be impossible to make clear record of all the species of roses that have been utilized in my experiments, even were it desirable to do so.

But it may be worth while to name a few of the more conspicuous ones that have been of exceptional service, and the hereditary factors of which have been blended and intermingled to produce the new types of roses.

The white and buff Banksias, which are abundantly grown in California for ornamenting houses, trees, and arbors, have proved of service because they are very rapid growers, and are practically without thorns.

The Rosa gymnocarpa, which is indigenous to British America and California, is a pretty and graceful rose, producing fine single flowers that grow in large clusters, and having the element of hardiness that characterizes the wild plant.

The Chinese rose, in numerous varieties (Rosa Chinensis), and the Japanese rose (Rosa rugosa), have made their influence felt in many hybrids. So also has the Wichuriana. The seedpods of the Japanese species are unusually large and handsome. The hybridization of the Japanese rose with the Bon Silene and with other strains, including the Hermosa, produced a number of admirable roses that I have introduced, including the Pipette, Coquito, and Peach Blow.

The General Jacqueminot, one of the best known of the hardy perpetual bloomers, is itself a hybrid—as indeed are all other cultivated roses, no doubt, could we know their precise pedigree.


Chilean Wild Roses
These Chilean wild roses have been carfully selected in Mr. Burbank's garden, but otherwise are unmodified. They will be used for hybridizing experiments; and not unlikely they will instill their qualities of hardiness and prolific bearing into their hybrid progeny.

It is a hardy and prolific plant, and its qualities are curiously prepotent when it is crossed with other varieties. This applies not merely to the form and color of the flower itself but to the entire structure of the plant. Its chief characteristics seem to have peculiar prepotency or dominance. But of course the latent characteristics of the variety with which the Jacqueminot is crossed may reappear in later generations.

In striking contrast with the virility of the Jacqueminot is the approximate sterility of the hardy old-fashioned Persian rose.

This has blossoms of the handsomest yellow color, and on this account was regarded as a desirable parent for hybridizing experiments, notwithstanding that it blooms for only a short season in the early summer. But not only does the Persian rose itself fail to produce seed, but its pollen seems to be sterile when applied to the pistils of other flowers or fails to reveal its character in the seedlings. For many years. I attempted to hybridize the Persian rose with the Tea rose, Perpetuals, Banksias, Multifloras, Bourbons, Wichurianas, and many others, but in no case did I succeed in making a useful combination. Nor was the experiment more successful when an attempt at a reciprocal cross was made. The pistils of the Persian rose failed to respond to the stimulus of pollen from whatever source. So, of course, there was no strain of the Persian rose in any of my hybrids. This variety has seemingly reached a stage where it can apparently be perpetuated only by division.


Blue Roses
Few types of experiment appeal more strongly to Mr. Burbank than those directed toward the bringing out of some obscure or submerged trait of a flower, such, for example, as an unfamiliar or unusual color. No one needs to be told that a blue rose is an anomaly. the color photograph shows Mr. Burbank's success in causing the rose to take on this unfamilar color.

Enough has been said to show that the rose is a very tractable flower. Indeed, the very fact of the number of its species and varieties sufficiently attests its variability and receptivity.

Moreover, the rose is entitled to be considered pre-eminently the universal flower. It doubtless excels all others in popularity and it differs from most others in that it is prized equally in its different varieties for its form, its color, and its fragrance.

As to all of these, to be sure, approximate perfection appears to have been attained with a good many varieties of roses. Yet the fact that new varieties are from time to time put forward shows that there is always opportunity for improvement. I have emphasized certain directions in which the improvement of the many varieties is possiblenotably in the matter of hardiness and resistance to disease.

THE CHANCE FOR NEW ROSES

But, in point of fact, the list of qualities that are taken into consideration by the connoisseur as well as the commercial grower of roses is so extensive that there is opportunity for development through selective breeding of almost any existing variety as to one or another trait that it lacks. Abundance of bloom, lasting qualities of the flower, beautiful buds, long stems, handsome foliage—these are qualities in addition to the fundamental ones of hardiness and resistance to disease that must be taken into account in estimating the value of a rose. Then there is one other characteristic of the rose which has hitherto scarcely been considered by anyone, yet which seemingly lies within the possibility of development. This is the matter of increasing the amount of pulp that encases the seed pod of the rose. So much attention has been given to the flower that no one has given heed to the fruit. But it is familiarly known that the rose belongs to the same natural order with the apple, the pear, and our other chief fruit growers of the orchard. So it is a reasonable assumption that this plant could be educated, were sufficient attention paid to the matter, to produce an edible fruit.

Even as the case stands, the fruit of some of the wild roses is sometimes eaten by children, though its proportion of pulp to seed is so small as to be almost negligible. And what has been accomplished with other members of the tribe makes it seem probable that the pulp could be developed and the seed correspondingly decreased until the fruit became quite transformed.

I have said that the rose is the universal flower. Doubtless it already takes first rank among the flowers that man has brought under cultivation.

But if it could be made to supplement its wonder ful blossom with a really valuable edible fruit, the pre-eminence of the rose among all the plants that man has placed under cultivation would be still more firmly established.


—There is a time element in the introduction of a new flower or fruit. In fact, no new plant development could be expected to make its way except very gradually at first; although it gains momentum with great rapidity after a time.

Peachblow (1893)
 
Coquito