Rose Society of Ontario pp. 53-56 (1926)
Breeding Roses for Canada
J. W. CROW, Hybridist, Simcoe, Ontario.

The hybrid-tea rose has been brought to such a wonderful perfection under glass that we are all anxious to grow flowers equally fine out of doors. Unfortunately, the greenhouse varieties, with their buds and flowers of beautiful form, their perfect stems and continuous blooming habit, are not robust enough for general garden cultivation in our inland Canadian climate. European novelties of recent years are not much more successful as they are predominantly H.T. in origin, and come for the most part from climates much milder than ours. Very few of them will endure successfully our hot summers and cold winters. We need in Canada a race of roses hardier than any we are likely to get from Europe or from under glass. There is no lack of material from which this hardier race may be developed as many very fine roses of the older, June-blooming type, are reliably hardy over a fairly large part of Canada.

We are much in need also of varieties less subject to disease, which could be grown successfully without spraying. The greatest difficulty I have had in undertaking rose breeding has been to secure reliable information on the susceptibility or resistance of varieties and species to black spot and mildew. Black spot is much harder to breed out than mildew as there are a number of good H.P.'s and H.T.'s not ordinarily troubled by mildew to any great extent. I have yet to find, however, any H.T. which under ordinary garden conditions is even measurably resistant to black spot. Most of them are very subject to it, especially the Pernetiana group which is giving us at present so many new shades of color. I have found in rose literature very little reliable information on this question and have been compelled to conduct careful tests for myself. For the past three years I have kept detailed and accurate records in my own garden, covering a total of 162 varieties and species. Spraying has been intentionally omitted in order to give full opportunity for infection. Of species, the following have been almost entirely free of both mildew and black spot: acicularis, blanda, ecae, hugonis, humilis, moyesi, rugosa, setigera, spinosissima, and wichuraiana. One plant of rugosa alba was badly attacked by mildew in the hot, dry summer of 1923 but under ordinary conditions this species is practically free. Of species-hybrids the following have shown nothing more serious than occasional traces of disease: Roserie de l'Hay, Agnes, F. J. Grootendorst, Baltimore Belle, Lady Duncan, New Century and Sir Thomas Lipton. I have not been able to get seed from any of these and believe them to be almost or completely sterile.

Among climbers, Dr. Walter Van Fleet, Climbing American Beauty and American Pillar have been practically free from infection although Van Fleet has shown slight traces of both black spot and mildew. The foliage of the other two seems perfect. Excelsa has been satisfactory but shows some infection at times. American Pillar is almost completely sterile but occasionally a seed will germinate. Its pollen seems useless and has given me nothing but failure. Van Fleet and Cl. American Beauty both contain a large admixture of tea or hybrid-tea, combined with wichuraiana. They both have flowers of good size and form and I am using them extensively. They are the only varieties I have found containing any appreciable infusion of tea or hybrid-tea, combined with disease resistance.

Next in order of resistance among climbers but very much superior in quality of bloom is Paul's Lemon Pillar. I have one beautiful specimen which has been under observation for three years and which is surrounded by very susceptible badly diseased varieties. It has shown very little of either trouble. It is a cross of Druschki and Marechal Neil, June-blooming only but producing flowers of the finest exhibition quality in every respect. It is truly a magnificent rose and one which seems to me of the greatest value for breeding purposes. It requires protection in winter.

I have tested 16 H.P.'s, the most resistant of which have been Magna Charta, Paul Neyron and Druschki, with Capt. Hayward not far behind. They are by no means free but if planted away from susceptible varieties would give little trouble and thrive wonderfully with little attention. Capt. Hayward bloomed freely last year over a period of two months, from mid-June to mid-August.

As already stated, I am not able to list any H.T.'s as possessing marked resistance to black spot. Some of the pernetianas seem almost or quite immune to mildew.

I am making use in two ways of the three valuable climbers mentioned above. First, as seed parents, crossing them with pollen from hardy species such as blanda, hugonis, rugosa and spinosissima. From these crosses it should be possible to develop hardy climbers of the greatest value.

Second, I am using pollen of Van Fleet and Cl. American Beauty upon the best H.T.'s, such as Ophelia, and on the best H.P.'s. Lemon Pillar is no doubt too tender to produce hardy seedlings when crossed with H.T.'s, and I am using pollen of it on the best of the H.P.'s.

A great many roses are more or less sterile and I have laboriously operated on hundreds of blooms of Testout, Teplitz, Laing, Paul's Scarlet and others, only to record complete failure. Pollen of the first three named gives good results when used on other varieties.

The technique of crossing roses is not difficult except that one must exercise great care to see that the pistils upon which foreign pollen is to be placed have not already received pollen from the anthers in the same flower. All roses I have worked with shed their pollen before the bud opens, sometimes as much as two days before. The bud to be used must therefore be operated on at least two days before it would open naturally. Even then a strong hand lens, magnifying 18 or 20 diameters, is strictly necessary to make sure there is no undesirable pollen present.

The proper handling of rose seeds to secure early and good germination requires special attention. Many rose seeds do not germinate under natural conditions until the second spring after sowing and they will often lie in the ground three or four years before starting. The reason for this delayed germination is now well understood, thanks to the researches of Dr. Wm. Crocker, who states that rose seeds in common with seeds of hawthorn, red cedar, dogwood, basswood and others, requires to pass through a period of after-ripening before it is capable of germination. Dr. Crocker finds this after-ripening process will proceed at temperatures between 40 degrees and 50 degrees Fahrenheit and that rose seeds stored moist within this range of temperature begin to germinate in 90 days and are completely germinated in 150 days.

Rose seedlings are very delicate at first and are easily destroyed by mildew, damping off, wet, frost or heat.

Seedlings of hybrid-tea roses flower in a surprisingly short time, often in 8 weeks or less from germination. A seedling may produce several flowers in the course of its first season and may sometimes show its full perfection during the second season. A new rose can be propagated and put on the market within four or five years from germination of the seed, which fact explains the ultimate failure and disappearance of such a large percentage of rose novelties.  They cannot be thoroughly tested in so short a time.

Valuable rose breeding for the colder parts of Canada is being done by Mr. F. L. Skinner, of Dropmore, Manitoba, an enthusiastic amateur gardener, also by Miss I. Preston, at the Central Experimental Farm, Ottawa, under the direction of Mr. W. T. Macoun, Dominion Horticulturist.