Plants and Gardens, 11(2): 131-136 (Summer 1955)
How to hybridise, and how hybridisation and selection have given rise to a strain of roses having sub-zero hardiness, resistance to disease, and beauty of bush and bloom
Walter D. Brownell

"WHAT makes a rose?"

First and foremost it is the garden that makes a rose. It is through the garden that gladness comes to the heart of the rose lover. This may well have been the thought in the minds of Mrs. Cranford and her late husband 26 years ago when they made possible the Cranford Memorial Rose Garden at the Brooklyn Botanic Garden, that has since gladdened the hearts of millions of visitors. A learned writer has said that a rose by any other name would smell as sweet. But would the rose in any other form bring as much joy to those many gardeners who love flowers?

The admiration for the rose, as you know, extends back for thousands of years. Until a century or so ago, its form had not changed very much. There were then only wild (species) roses because hybridizing, or cross breeding, had not begun. When hybridizing did begin, it was believed by some that this process carried something new and magical.


It is now well known that the factors in the constitution of plants, called genes (character determiners), crossed with those of another, produce only a recombination of the characters of the two parents. And yet, we marvel at the greater beauty of modern rose blossoms as compared with the flowers of species roses — the ancestors of all modern roses. The hybridizer, by pollinating one variety with another, merely sets the stage. He can add nothing.

Nature performs the miracle of reproduction. That miracle combines some of the characteristics of one parent with some of those of the other to form seedlings of the next generation.

Among the marvels of nature’s miracles, there is more that can happen. At infrequent intervals changes of character may suddenly take place even though no crossing has been performed. Such variations are called mutations or sports.

Thus species roses grew in the wild practically unchanged, as to man’s purposes, for thousands of years. Then man with the pollen brush and by selection from nature’s variations, greatly speeded up the process by which good new varieties arise. There are now several thousand varieties of roses that may appeal to the whims and tastes of every fancier.

Whom have we to thank for having thus attained the lofty heights of the Queen of Flowers? There are hundreds who have labored to this end — the rose hybridizers of America and of the world. They are too numerous to mention here, but all have helped to mold the beauty and the fragrance of modern roses.

I would like to tell you a little about the work of the Brownells of Little Compton, Rhode Island (of whom you have probably never heard); old in years, young in their hearts, and eager in their minds to continue toward their ideals and add a little to garden rose betterment.

Mr. and Mrs. Walter Brownell in their experimental rose garden at Little Compton, Rhode Island.


Soon after our wedding we started a small rose garden. We were both fond of roses, and the rose catalogs told us how easy it was to have beautiful blooms all summer long. We expected it. We tried it. We failed. The plants developed black spot; the leaves fell off in the summer; the bushes died in the winter. The question that came into our minds was not how to produce more beautiful roses — they were indeed beautiful — but why were not the bushes more sturdy?

What they needed, it seemed to us, was greater vigor, longer life and the ability to survive cold winters, and freedom from black spot. They should also have more cumulative growth, like plants in the wild, and more constant blooms in greater abundance.

Can you imagine a young couple starting a hybridizing project with all those objectives? Little did we know what we were then undertaking — we can be excused only on the ground of ignorance. There was a virgin field ahead. Several leading scientists became interested and were eager to cooperate.

Finding the Parents

As I indicated in the beginning, it has been shown that all plant betterment must come from recombining the characters of parent plants or through mutation or variation in nature. We therefore devoted the first 10 years to study and inspection, to determine the most appropriate material for the basis of the operations. The garden roses then in existence did not possess the necessary requirements. It therefore seemed advisable to select some species rose that would, through hybridizing, fortify the Hybrid Teas and lift them up to meet nature’s requirements in the wild.

There was no reason why this should not have been done before, except that much labor with great expense was necessary to breed successfully at the same time for plant sturdiness and a beautiful Hybrid Tea flower.

Rosa wichuraiana, which most of us know as the Memorial rose, was chosen for its vigor and resistance to cold and disease. Since it is a low-growing or creeping vine with a large cluster of small white flowers, blooming only once in the spring, it needs must be a long route to the swapping of characters to combine the beauty of large Hybrid Tea blooms and upright bush characters with the sturdiness, vigor, and resistance to cold and disease of the species. The Memorial rose resists cold to about 15°F. below zero, and it is nonsusceptible to black spot.

These characters had already been transmitted to descendants known as the class of Large-flowered Climbers which bloom only once each season. Familiar examples are Mary Wallace and Dr. W. Van Fleet.

It soon became evident through tests that winter resistance could be bred into Hybrid Tea roses, but the problem of getting seedlings nonsusceptible to black spot was most discouraging. You may be surprised to learn that today, after millions of crosses made over a period of more than 40 years, we have but nine Sub-zero Hybrid Tea varieties that have inherited from Rosa wichuraiana its complete nonsusceptibility to black spot, and only one of these has yellow flowers. But many of the others produced are much less susceptible than most roses, and the research has progressed so far that you may be assured that in the decades to come there will be no reason to grow roses that defoliate from black spot.

How Crosses Are Made

Perhaps some of you would like to know how the process for extensive hybridizing or cross breeding is carried on. With us, it begins at rose time, during college and high school vacation. Assembled in the field are perhaps a dozen girls interested in genetics, botany, biology, and the like. Each is equipped with small scissors, glassine bags, tiny rubber bands, and narrow strips of aluminum inscribed with a number to identify the selected pollen of the male parent.

About 2 days before the petals of the seed parent flowers open they are removed and the anthers snipped off so the flower will not be self-pollinated. Then the seed parent is covered with a bag to protect it against unwanted pollen. The rubber band promptly applied holds the bag in place. Two days later, when the pistil is sticky and receptive, the selected pollen gathered 2 or 3 days before is applied with a small brush, and the bag replaced. The aluminum tag is wound just below the bag.

That is all there is to it except to add that these girls are really interested; for what else could hold them in the hot sun all day long, under broad-brimmed hats, doing that same thing over and over again; and a nearby beach cooled by breezes and refreshing surf. But — no swim for them, only that same thing day after day, each girl making five hundred crosses daily before she goes home.

The seeds ripen by Thanksgiving time and are planted in flats in the greenhouse before Christmas. They germinate in the late winter and early spring, to be planted out in a field as soon as the frosts are over. There are about 2 acres of them totaling annually some 20,000 plants, in rows that placed end-to-end would extend 3 miles in length. They have to be scouted during the summer nearly every day for selections to be tested during the next 3 years, for introduction, or to be destroyed. On the average, only one acceptable variety is found in that annual lot of 20,000.

Seedlings change during their early-life, much as children do. Some look promising at first, later to be disappointing; others that are scarcely noticed the first year become very interesting later. It is usually 7 years from the pollination of the parents of a new variety to its introduction.

Thus it is that we have been able to breed roses as large and beautiful as any, all Rosa wichuraiana hybrids, in the classes of Hybrid Teas and hardy once-blooming climbers, that can take 15° below zero without protection.

Another Development

Another thing has happened at the gardens in Little Compton — something quite new and different, something sought for a century by rose breeders, something of interest to all rosarians.

Today there are growing throughout the country in rose beds Hybrid Teas and Floribundas, bushes of moderate height that bloom more or less throughout the growing season. Then there are Climbers and Pillars that cover trellises and the like, that bloom only in spring — and the latter do not bloom the first year planted. There are still other Climbers that have limited reblooming habit.

The Technique of Hybridizing

Hybridizing on a large scale as commercial rose growers do it is fascinating work, but is work nevertheless. The amateur can enjoy the satisfaction of hybridizing with practically no work at all. These diagrams, and Mr. Brownell’s description on the page opposite explain how it is done.

Left, bud of female (seed) parent about 2 days before it opens. At this stage petals should be
removed leaving flower as at right, showing stamens (male) and pistils (female).

Stamens are removed and flower is covered with small bag for a day or two until stigmas (tips of pistils) become sticky.

Pollen is collected from anthers of male parent and applied to sticky stigmas with a camel’s hair brush. With brush technique it is important to dip brush in 95% alcohol before changing to different pollen for a new cross. Brush should be dry before re-use.
The amateur who does not wish to bother collecting pollen can pull the petals off the male flower and use the cluster of stamens themselves as a brush, rubbing the pollen directly onto the stigmas.
The pollinated stigmas are immediately covered with a bag, and labeled with the names of the parents. When hips (rose fruits) start to swell, bag may be removed. Seeds should be stratified before planting to insure good germination. They are placed in jars in damp (not wet) peat moss and kept in a refrigerator for about 3 months. Then they are planted in flats, or if weather permits, in beds out-of-doors.

Why have we not had tall rose bushes, self-supporting, that bloom the first year like Hybrid Teas and on canes the year those canes grow, year after year? Why not roses that form bushes 6 or 8 feet tall, everblooming, or that climb to the roof of a garage and there bloom on all stems, branches, and canes as fast as they can grow, until frost?

The answer is clear and simple:

The everblooming Hybrid Tea and the tall-growing, once-blooming climbers will not combine everbloom and tallness by breeding; and the seedlings of those crosses will not produce the desired flowering characters. The rose hybridizers have sought that combination for more than 100 years in vain.

But now comes Mother Nature who has produced by mutations over a period of many years a number of different varieties that do contain in their constitution both tallness and everbloom; in their fullness, selections from these have produced a new race of Everblooming Climbers, that repeat like Hybrid Teas. Nature has done it.

Hundreds of varieties in various forms and colors are being brought into being each year by special breeders; and from these one or two varieties are selected for distribution.

Future Outlook

Perhaps some readers would like an interpretation of the future development of this new and complete combination of the everblooming quality with the vigor and tallness of Pillars and Climbers, that nature has through its processes of evolution given to the Rose World. It is something of very great importance.

In this connection it is well to note that there can be many varieties with an incomplete combination of everblooming and once-blooming qualities. Some of those that have previously been obtained are well known, such as New Dawn, Dr. J. H. Nicolas, and Orange Everglow. But these do not have in their constituions the fullness of that combination that the selected varieties of this new race have.

Just how will such a new race influence rose gardens of the future, during the next half-century? For comparison, let me greatly exaggerate the situation by reminding you of past developments not promptly foreseen. Had you heard my bellowing voice in 1880 over one of the fifteen telephones in Providence, Rhode Island, would you then have believed that that city would now be equipped with 100,000 phones? Had you, a few years later, been in the contest of horseless carriages racing from New York’s 5th Avenue Hotel to Yonkers, less than 20 miles away, the winner taking nearly 6 hours, could you have dreamed of crowded highways as they are today? When we read of Marconi’s wireless telegraph succeeding in spanning the Atlantic, could any of us have visualized himself sitting at home with today’s television?

Author photo: The yellow V for Victory,
one of the Brownell sub-zero Hybrid Teas.

Of course these things are of interest and importance to everyone while a new type of rose plant can only be of most interest to gardeners. But there are many million gardeners! As the new rose combines sturdiness, tallness, and the beauty of everbloom, it can end many a rose gardener’s discouragement. From tests it is evident that these new roses have the hardy sturdiness of the Rosa wichuraiana climbers. There is no limit to the number of varieties that may be produced.

Here is a summary of the outstanding qualities of this new race of Everblooming Climbers:

They bloom the first year they are planted as freely as do Hybrid Teas. They can be cut back like Hybrid Teas to any height desired.

The canes bloom as they mature, in clusters or racemes, the same year they grow.

The stems and canes continue to branch and bloom until frost.

In color, form, size, and fragrance the blossoms compare favorably with those of the present Hybrid Teas.

Some varieties are sufficiently self-supporting to form that needed specimen bush for the lawn, 5 to 8 feet tall.

Some can be grown as pillars or climbers on racks or trellises.

Others have branched canes to lay on top of some building, such as a garage, to bloom there like Hybrid Teas and still others will lie by the roadside, on banks, or over walls and fences.

Their sturdiness renders them as easy to grow lilac, philadelphus, and forsythia.

What other bush is there that grows north of the semi-tropics today, that can show such variation in plant form with such beauty of flower color, and also bloom so constantly? There are in the breeding grounds at Little Compton, Rhode Island, such plants 6 years old, the first 2 years hoed and cultivated, the last 4 years in competition with weeds and brush and having no cultural attention. From these are gathered thousands of hybridized seeds each fall.

This, then, is our prophecy of “What makes a rose” for the future, based on over 50 years of nearly full time work with roses.

Sub-Zero* Hybrid Teas

(Bloom All Season)
Handsom Red — glowing red
Queen o’ the Lakes — deep red
Red Duchess — rose-red
Curly Pink — two-toned pink
                Lily Pons — white, yellow center
                King Boreas — lemon -yellow
                Yellow Ruffels — yellow
                Orange Ruffels — glowing orange
Everblooming Pillars
Eight varieties of climbers that bloom all season like Hybrid Teas
Resistant (relatively immune) to Blackspot
Pink Bouquet
Orange Ruffels
Yellow Ruffels
Red Duchess
Pink Princess
Dolly Darling
Curly Pink
Sub-Zero* Floribundas
(Bloom All Season)
Dolly Darling — pink
Yellow Curls — yellow
Lafter — orange and yellow
Anne Vanderbilt — copper
Brownell Hardy Climbing Roses
(Bloom in Early Summer)
Climbing Red Duchess — red
Golden Climber — yellow
      Golden Orange Climber — orange
      Climbing Break O’Day — orange to apricot

*Ability to withstand winter killing is more than merely a resistance to cold; even perfectly hardy roses may die in winter if they have received improper care or are in poor condition from any other cause. — Ed.