American Rose Annual pp. 37-41 (1916)
Some New Roses Introduced by the Arnold Arboretum During the Past Decade
By E. H. WILSON, Arnold Arboretum
Author of "A Naturalist in Western China"

EDITOR'S NOTE.—There is little realization of the immense value to gardens and parks of the work done under Prof. C. S. Sargent at the Arnold Arboretum, at Jamaica Plain, near Boston. In addition to the collection and planting of everything native to America that will grow outdoors there, systematic investigation of the rest of the world's plant resources has been undertaken. One of the chief investigators has been the great botanist and writer, E. H. Wilson, who has conducted four notable expeditions to western China during eleven years, with the result of adding more than 1,500 plants hitherto unknown to our gardens. Mr. Wilson's books, articles and lectures are alike intensely interesting. He has given particular attention to the rose, and what he here writes may be accepted as authoritative.

IT has been said that "Roses are made—not discovered." This is largely true since nearly all the roses in general cultivation have been produced in gardens. But bricks cannot be made without clay, neither can garden roses arise spontaneously. In both cases, raw material is absolutely necessary. Thanks mainly to the labors of the last hundred years, the garden roses of today have reached a high state of perfection, but in their evolution only a comparatively few species have played a part. When we consider for a moment the array of wild roses which have so far not been utilized, and give due heed to the fact that the hybridizing of lowly forms has largely given us what we enjoy today, it would be fatuous to imagine for a moment that the rose has reached its zenith.

(Photograph supplied by Mr. E. H. Wi1on.)

For more than forty years the Arnold Arboretum has been busily, persistently, and continuously employed in bringing together from every part of the north temperate region every kind of hardy or possibly hardy woody plant. As one result of these activities many new species of roses have been brought into cultivation. To go over the whole field of forty years would entail more labor than I have leisure to give and require more space than the Editor would allot. As a compromise, therefore, I propose to mention a few of the more important species of roses, with one exception all from China, which during the past decade the Arnold Arboretum has been instrumental in introducing to this country.

About twenty years ago the horticultural world was electrified by the appearance of a rose styled "Crimson Rambler." It fired popular imagination; it was a new type of garden rose and everybody wanted it. The rosarian seized upon it and the popular demand it created, and a new group of roses, which has completely transformed the rose-garden and pergola, has been evolved. In June of 1913 the wild prototype of the Crimson Rambler blossomed for the first time in this country in the Arnold Arboretum, where it was raised from seeds collected in north-central China by William Purdom in 1910. This wildling has been named Rosa multiflora var. cathayensis, and is a rose of rare beauty and of great potential value. The flowers are borne in large clusters, as in all Rambler roses, and are clear pink, each 2 to 2 1/2 inches across, single of course, with a mass of yellow stamens; the foliage is perfect, and the plant is a vigorous grower and is absolutely hardy.

The rose to which the Swedish botanist Thunberg, in 1784, gave the name "multiflora" has large trusses of small white flowers and grows wild only in Japan and southeastern Korea. It was introduced from Japan to France about 1862. In 1905, John G. Jack discovered in Korea and collected seeds of a rose somewhat similar to Thunberg's but with larger flowers. When the plants raised from these seeds flowered the rose was found to be distinct from all known species, and was appropriately named R. Jackii. The stems trail flat over the ground, the leaves are lustrous green. The pure white flowers are fully 2 inches in diameter and are borne in wide many-flowered dusters. It is perfectly hardy and blossoms in late June or early July, fully two weeks later than R. multiflora, and is a first-rate garden plant to which the hybridist should devote some attention, with a view of extending the length of the flowering season of Rambler roses.

In 1816, at Charleston, S. C., the Chinese Monthly rose (R. chinensis) and the Musk rose (R. moschata) were successfully crossed and the world came into possession of the first Noisette rose. This strain subsequently produced such grand old roses as Solfaterre, Aimée Vibert, Lamarque, William Allen Richardson, and others. They were a little fastidious, perhaps, but the color and fragrance were delightful, and it is much to be regretted that the class should now have fallen into disfavor. Both parents are tender, and the Musk rose is of weak constitution. But there are now known other Musk roses: One from the Himalaya (R. Brunonii) has in California been crossed with the prototype of the Tea rose (R. gigantea), and there have resulted such roses as Belle Portugaise, Montecito, Montariosa, and others, constituting a new race of roses, valuable for California.

The Himalayan rose is also tender in New England, but China comes to the rescue with some six different species of Musk rose, and one of these (R. Helenae) has proved perfectly hardy in the Arnold Arboretum. Raised from seeds collected in central China in 1907, this rose flowered with us for the first time in 1913. The plants are now 5 to 8 feet tall and more in diameter, with arching stems, and in late June were covered with masses of pure white and delightfully fragrant flowers. The flowers are about 1 1/2 inches inches in diameter and the stamens are golden yellow; the foliage is light green, of good size, and of much substance. Here again is a hardy rose of great beauty and of untold potential value in the breeding of new races of roses.

More hardy yellow-flowered roses are needed, and in R. Hugonis there are great possibilities. This beautiful rose came to us from the Royal Gardens, Kew, where it was raised from seeds received from north-central China in 1899. It is an upright-growing shrub 6 to 8 feet tall and more in diameter, with slender and spreading branches. The fragrant flowers, each about 2 1/2 inches across, are produced all along the branches, and so freely are they borne that the branches become yard-long sprays of soft yellow. The leaves are small and of a pale green hue, but the foliage is ample, and as I write in mid-November is still on the shrub, and has assumed a dark purple tint. (See illustration, Plate V, facing page 32.)

In habit, foliage, and manner of flowering, R. omeiensis much resembles the foregoing, but it is a more vigorous shrub, growing 15 to 20 feet tall on the mountains of central and western China, and the flowers are white and smaller, each having only four petals, arranged like a Maltese cross.

These two roses with their yellow and white blossoms are excellent companions, making fine specimen plants. It is also probable they would make valuable hedge-plants. They are among the earliest of all roses to open their flowers.

One of the most beautiful of all hardy roses is R. Moyesii, with saucer-shaped flowers 2 inches in diameter, which vary in color from rich reddish crimson to velvety crimson. This rose has upright stems and spreading branches, and is a very vigorous grower. Very similar to the preceding in habit of growth and equally vigorous are R. caudata, R. Davidii, R. banksiopsis, R. saturata and R. corymbulosa, all new species. In these the flowers vary in color from pink to rose and red, and they differ one from another in their leaves, quantity of flowers in each truss, and in many technical and essential points. All have distinct charms and are valuable additions.

Two distinct species with stout-arching stems and spreading branches densely armed with large prickles are R. setipoda and R. Sweginzowii, and these produce their rose-red flowers in large clusters about the end of June. More slender growers with twiggy branches are R. sertata, R. multibracteata and R. Willmottiae, which have pure pink to rose-colored flowers and small gray-green leaves. Lastly I may mention the low-growing R. bella, which opened its flowers for the first time under cultivation during the past summer. This is a dense, compact shrub, growing 2 1/2 to 4 feet tall, and in June it was, literally speaking, a blaze of rich red flowers each 2 inches across. Like all the other roses mentioned here it holds its foliage in good condition very late in the fall.

In gardens large and small wild roses for their own sake deserve wider recognition than is at present accorded them, for in addition to the beauty of their flowers, so freely produced in season, they bear in the autumn masses of brilliantly colored fruits.

Incomplete as this short note is it would be much more so did I in closing omit mention of the work accomplished in the field of rose-breeding by the Superintendent of the Arnold Arboretum, Jackson Dawson. This grand old gardener has ever been a zealous devotee of the rose, and, his multifarious and onerous duties notwithstanding, has found time to raise by hybridization a number of valuable garden roses, while in some groups he was the pioneer. The Dawson rose (General Jacqueminot x R. multiflora) was one of the very first of such crosses made, and R. Jacksoni (R. rugosa x R. Luciae) was perhaps actually the first rugosa x Wichuraiana hybrid. Other good hybrids raised by him are W. C. Egan, Arnoldiana, Lady Duncan, Farquhar, and the Sargent rose.