Canadian Rose Annual 1961: 90-91
Need for a Hardier Understock
Percy H. Wright, Saskatoon, Saskatchewan

A ROSE understock of superb hardiness was originated by the late Professor J. T. Maney, peach specialist at Ames College, Iowa, as an after hour project. He developed it by crossing a thornless variety of the Japanese multiflora rose, the commonly used species for understocks in North America, with Rosa blanda, the native wild rose of the Great Lakes area, which is also thornless.

Inevitably he got a thornless rose and designated it Ames 6. In many respects it is the ideal understock as it is hardy most winters as far north as Saskatoon, Saskatchewan. It is a strong grower and rarely produces a sucker but it has two deficiencies. First, when propagated by hardwood cuttings its 'take' is lower than that of multiflora and, secondly, its bark is thinner, making it a little harder to work. For these reasons U.S. nurserymen turned it down after a few trials. In an area where additional hardiness is generally desirable, but not vital, this rejection is understandable—but in Canada it is a different story.

Ames 6 has been used as an understock for hardy roses in a limited way by several Saskatchewan nurserymen, but so far as I know no Canadian producer of hybrid teas or similar roses has ever tried it out—not even for experiment's sake. This is hard to understand and I am afraid indicates a lack of enterprise.

I am not suggesting that Ames 6 would have taken over if tried, probably it would have been discarded just as it was in the U.S.A., however, trying it would have focused attention on the need of a hardier understock; and might have set off a project to breed a hardy understock right here in Western Canada.

In fact it did have some success in this respect as I crossed it with 'Betty Bland' and other hardy roses, but my effort was to get a still hardier understock for hardy roses, and not to breed an understock for hybrid teas. I have several new varieties, the most outstanding being 'Eureka' but I doubt very much if it is the answer. It comes from hardwood cuttings more easily than Ames 6 but is a weaker grower and no hardier. Someone farther south should have hack-crossed Ames 6 to its multiflora parent.

Considerable claim is being made that canina is somewhat more hardy than multiflora, and while this may be true it has been shown that some caninas are hardier than others. However, no strain of canina is of maximum hardiness and thus able to impart this quality to tender roses.

Just how much extra hardiness can be given by an understock is not known, however, one experiment that has been made would indicate that it is considerable. Mr. George Bell of Vilna, Alberta, which is north of Edmonton, grafted hybrid perpetuals on native wild rose roots back in the early days of prairie settlement. When I last heard of these early grafts, which would be in the early fifties, they were still alive. The bushes, of course, received yearly protection but even so this is a remarkable story of success. Hybrid perpetual bushes surviving for forty years would be something of a record, even in southern Ontario.

In any event it is very clear that there is a wide-open opportunity for the development of a hardier rose understock in Canada, and why it has not been seriously attempted is beyond my understanding.

Rose Understocks