Monday, June 11, 2012

Canadian and Rugosa Blackspot Review

'Hunter'....of course
This post is the second in a series of three Mondays on which I review a major group of my roses for blackspot susceptibility.  Last week, of course, I reported my Griffith Buck roses.  Today, I'll note the damage on my AgCanada-bred roses and selected Hybrid Rugosas.  Of course, many Rugosa Hybrids who have very thick and rugose leaves are not susceptible at all, and I can vouch for Blanc Double De Coubert, Souvenir de Philemon Cochet, Scabrosa, Purple Pavement, Pink Grootendorst, and F. J. Grootendorst as blackspot free.

As before, the first number is the estimated percentage of leaves with blackspot and the second number the estimated percent defoliation. And now, without further ado, the Canadians and Hybrid Rugosas: (with a few odd roses thrown in that were bred in Canada but not released by AgCanada).

Prairie Joy 0%-0%
Morden Blush 10%-5%  (this rose is my blackspot "indicator")
Marie Bugnet 0%-0%
Therese Bugnet 0%-0%
Cuthbert Grant 0%-5%
Morden Sunrise 10%-20%
Morden Centennial 5%-10%
J.P. Connell 60%-80%
David Thompson 0%-0%
Hope for Humanity 0%-0%
Adelaide Hoodless 5%-5%
Champlain 0%-0%
Henry Hudson 0%-0%
Alexander MacKenzie 10%-70%
Morden Ruby 0%-0%
John Franklin 30%-20%
Morden Fireglow 20%-10%
Winnepeg Parks 10%-50%
William Baffin 0%-80%  (leaf loss may be due to drought)
Survivor 5%-5%
John Davis 5%-5%
Martin Frobisher 0%-0%
Prairie Dawn 10%-60%

Hybrid Rugosas:
Conrad Ferdinand Meyer 5%-0%
Sir Thomas Lipton 0%-5%
Moore's Striped Rugosa 0%-0%
Robusta 10%-20%
Linda Campbell 20%-10%
Hunter <5%-0%
Rugelda <5%-0%
Topaz Jewel 0%-0%

As you can see above, the Canadian roses are hit and miss on blackspot susceptibility with John Franklin, Alexander MacKenzie, Winnipeg Parks, Morden Sunrise, and J.P Connell almost sure to have a little blackspot.  In fact, J.P. Connell always lies somewhere between struggling for life and trying to die for me and I would grub it out if I only had the courage of the Cowardly Lion (a little Kansas-Wizard of Oz reference there).  Morden Blush, interestingly, is usually one of my earliest roses to show blackspot, but this year it isn't as affected.

Rugosa blood, as you can see, does not necessarily mean that blackspot can be forgotten.  Robusta and Linda Campbell have both been a bit disappointing to me in that regard, but I keep them around for their cardinal red color and dependable repeat. Certainly, it seems the more rugose the foliage, the more blackspot resistant in this group.

Next Monday I'll spill beans on the Old Garden Roses that I grow.

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