American Rose Annual 13: 29-34 (1919)
Rose-Breeding Notes for 1918
By DR. W. VAN FLEET
Department of Agriculture, Washington, D. C.

Editor's Note.—As will appear on perusal of these notes, the war excitement has not prevented real progress toward the development of better roses for and in America. Dr. Van Fleet uses rare ability and insight in his patient work, and discouragements do not daunt him. Taken in connection with his articles in the 1916, 1917 and 1918 Annuals, and with his delightful discussion of perfume roses on page 14 of this book, his contributions to recorded real rose knowledge are of unique value.

ROSE-BREEDING, for the development of hardy garden varieties at Bell Experiment Plot, Glendale, Md., was conducted on a more extended and apparently more successful scale in 1918 than in former years. A greater number of new and previously untried rose species becomes available each season and are utilized to the utmost in the hope of gaining characteristics of value.

A collection of rare old garden roses and little-cultivated western species that may come into partial bloom the coming summer has been most kindly supplied by the Arnold Arboretum of Boston. This should open up new fields of endeavor when fully available.

It is, perhaps, not profitable to recount the pollinations made during the past season. The final outcome in the way of blooming seedlings bears such small relation to the hybridizations actually effected and the number of apparently good seeds secured, even under the most painstaking cultural conditions, that disappointment is almost sure to follow high anticipations, while the quality of the offspring of the most promising crosses is apt to fall below expectations. Nevertheless, persistent work in any line of effort is likely to bring encouraging results which may in time measure up to our more reasonable aspirations.

As cheering notes of progress we can report considerable improvement in the newer hybrids of Rosa rugosa, R. Hugonis, R. Soulieanea, and R. Moyesii. The range of color in R. rugosa is steadily being extended, and now covers in single and double, constant-blooming forms about all shades except yellow, from the clearest of whites to glowing crimson.

Yellow flowers may be had by the use of pollen from Persian Yellow, Harison's Yellow, R. Hugonis, and R. xanthina, but the colorings are far from pure and the blooms leave much to be desired in the way of size and finish. The R. rugosa X R. Hugonis crosses are very early and vigorous, with remarkably handsome foliage and a profusion of cream- and primrose-tinted blooms, some of which produce seeds. It may be that in time we will get bright yellow-flowered Rugosas, with all the added attractions of the type.

Several exceptionally attractive crosses of R. rugosa with Triomphe Orleanais came to notice last year. They are characterized by compact habit, dense glossy foliage and upright shoots topped with immense, broad clusters of bright, cherry-red, semi-double flowers an inch or more in diameter. The spring bloom clothes the entire plant, and this is followed at frequent intervals by other crops culminating in a secondary grand outburst in September. One individual has the petals fringed or laciniated like a dianthus, and the pungent Multiflora fragrance derived from the pollen parent further emphasizes the Scotch-pink effect of the bloom-clusters. A white-flowered hybrid of R. rugosa and R. multiflora has already been described under the name of R. Iwara, and the newcomers should doubtless take their place in this new group about to be formed. The main effort in the development of R. rugosa is to secure high-class blooms of the Hybrid Perpetual and Hybrid Tea types on vigorous, hardy, disease-resistant plants, and continuous progress is being made in this direction.

*See Mr. W. C. Egan's account of this rose on p. 22 of this Annual, and the picture of it facing page 17 of the 1916 Annual.—Editor.

Rosa Hugonis is affording greater encouragement in hybridization than in previous years. The ideal yellow garden rose is far from being in evidence, but some of the R. Hugonis hybrids are worth working with. The blend of R. Hugonis and R. spinosissima altaica, a superior white-flowered form of R. spinosissima* from the Altai Mountains of southern Siberia, gives rise to strong, erect plants with glossy foliage, densely covered with well-finished single and double blooms, intermediate in size and coloring between the parents. The effect of these elegantly formed bushes, some six feet in height the third year from seed, is very striking in early spring, and the foliage endures well until early winter, turning a good yellow in autumn. As some of these hybrids produce seeds, it may be possible to develop brighter coloring in future generations, without material loss in habit.

The Scotch rose, or R. spinosissima group, appears to "nick" better with R. Hugonis than the Rugosas and other hardy species, some of which produce veritable freaks in the way of first-generation hybrids, though succeeding progeny may show improvement.

The first R. Hugonis seedling containing Hybrid Tea blood has bloomed for three seasons and is interesting, if not beautiful. The pollen parent was most likely Radiance, and the large, double, pinkish yellow flowers afford strong resemblance to that excellent variety in form and fragrance. The plant is healthy, hardy, and has grown over four feet in height. It fruits sparingly and shows signs of a fair increase by suckers.

Rosa Soulieana, a species from which little was expected, continues to give excellent results. Mention was made in the 1918 Annual of attractive hybrids of R. Soulieana with R. Wichuraiana and the white-flowered form of R. virginiana or R. lucida. These have been distanced by a blend of R. Soulieana, R. setigera, R. Wichuraiana, and R. odorata in the form of the old Tea rose, Devoniensis. In this complex hybrid, R. setigera appears to have furnished the hardiness, R. odorata the size and finish of the wonderfully numerous, pure white, single blooms that cover the entire plant in season, and the other two species the glaucous, resistant foliage and strong, arching growth that render the vigorous plants practically independent of support. This variety has been given the provisional number of W. S. 18, and as it fruits with great freedom may be of further utility in breeding.

Rosa Soulieana has also produced double blooms, of small size but great perfection of outline, in our breeding experiments, and in the second or F1 generation gives rise to very dwarf, ever-blooming plants of the general character of R. Pissardii (R. moschata nastarana), a Musk rose hybrid greatly favored in old gardens.

We may yet secure some fine bedding varieties of R. Soulieana of the dwarf Polyantha type. The fragrance of R. Soulieana, preserved in its hybrids, is faint, but perhaps the most pleasing of any of the species of the Musk rose group.

Owing to its poor seeding abilities when grown as grafted plants on heavy soil, less progress has been made than was hoped for with R. Moyesii, notable among wild roses for the deep red coloring and waxy texture of its widely expanded blooms. Now that our plants have been transferred to the sandy loam of Bell Experiment Plot, and have become established on their own roots, seeds are more freely borne, and a fair number of hybrids are under way. Pollen was plentifully produced, even when the fruits failed to mature, and a few early crosses, the result of applying it to the stigmas of other species and varieties, have sufficiently developed to show prospective value.

Plate VI.
New Hybrid rose, "W. M. No. 5" (unnamed Wichuraiana-Setigera hybrid x R. Moyesii).
Originated by Dr. W. Van Fleet (From ARA 1920)

The most striking is W. S. No. 5, with an unnamed Wichuraiana-Setigera hybrid as seed parent. This, at four years from germination, forms a fine plant with arching shoots six to eight feet high, covered in June with blackish crimson single blooms nearly three inches across. Even the filaments of the stamens are colored, as in R. Moyesii, but the petals have a white base, making a striking contrast with the deep coloring of the other portions of the flower. The plant appears exceptionally healthy and hardy, and will be propagated for dissemination and trial.

Of another type is R. Malyi X R. Moyesii, a compact little upright bush with blooms almost identical with Moyesii, but likely to be produced with greater profusion. R. Malyi is a rarity, found only on Monte Santo in Dalmatia, and is thought to be a possible natural hybrid between R. pendulina and R. spinosissima. It is a most desirable, dwarf, early-blooming wild rose, with bright crimson flowers and of compact habit, but appears quite difficult to propagate. The hybrid with R. Moyesii may prove very useful for hedges and rockwork.

Rosa setipoda, until within the last two years, has been an even shyer seed-producer than R. Moyesii, notwithstanding its profusion of bloom. A few hybrids, produced by the use of R. setipoda pollen on other species, are under way. Only seedlings of R. rugosa X R. setipoda have yet bloomed, and most of them show imperfect development of the flower-buds. One individual has promise as a dwarf cluster-rose of distinction.

The premier English rose of 1918 appears to be Mermaid, said to be a product of R. bracteata, the Macartney rose, and a tea-scented variety. The blooms are described as very large, cream-yellow, with conspicuous anthers. Mermaid has received about all the available honors and medals of the season, and doubtless will be widely grown wherever it is sufficiently hardy. Good varieties are to be expected when R. bracteata and R. odorata in choice forms are bred together, and many rivals to Mermaid may appear in the future. Our endeavors here, however, are to secure hybrids of R. bracteata able to endure the exacting climates of our northern and prairie states.

Thus far, R. bracteata X R. carolina has given most promising results. Most of these hybrids endure zero weather, and in the single forms develop the longest and most perfectly formed buds of various pleasing shades of pink that we have ever seen, some opening to nearly five inches in diameter, but the plants are scrawny and the foliage easily infected by black-spot at the Bell Experiment Plot. In one hybrid, however, R. bracteata so greatly predominates that plant, foliage and flowers almost duplicate that species, R. carolina only showing in the sterility of the blooms and in complete hardiness in our locality. The plant came through the dreadful winter of 1917-18 in a very exposed situation, absolutely without injury, though the parent species from which the seed was taken, grown against a south wall, was killed to the soil-line. This hybrid variety should be tested under more severe climatic conditions.

One plant of our three seedlings of Harison's Yellow—the entire outcome of years of seed-sowings—bloomed quite profusely the past season, the third from germination. The plant appears rather nearer R. spinosissima than R. lutea, one of the reputed parents of Harison's Yellow, and the blooms, though well finished and more double, are lighter in color than those of this most valuable variety. It, however, responds to cross-fertilization and perfects seeds with foreign pollen, which has never been the case in our trials with Harison's Yellow, though countless pollinations have been made extending over a period of twenty years. If the seeds of the new seedling grow, progress may be made toward the evolution of new yellow hardy roses better suited for garden use. The fruits of the seedlings were black and smooth, like those of R. hispida and R. spinosissima altaica, allies of R. spinosissima, instead of bronze-purple and spiny as with the parent plant. About 600 self- or chance-pollinated seeds of Harison's Yellow, from diverse localities, were secured and sown in September, 1918, in the hope of raising more seedlings. Seeds of this variety germinate the following spring, if at all, but the proportion that materializes in plants is remarkably small. Our trials have produced only the three plants mentioned out of many thousands of seeds sown.

The showy fruited rose species are being bred together in the expectation of getting superior varieties, and some attempt will be made to further develop the fragrant foliage of the Sweetbrier, R. rubiginosa, R. agrestis, R. lutea, and others. It seems to be within the bounds of possibility that this most agreeable fragrance can be intensified.