Don't know if this is any help, but I live north of Kingston, Ontario and I have an Abraham Darby as well as many other David Austin roses. The only bit of information that might be usefull is, to avoid winterkill, I cut back to about 2 ft., surround each plant with a large circumference of chicken wire and fill to about 1 ft. depth with mulched leaves in the late fall. Last year, after a winter with minus 30 degrees for several days, I only lost 1 of 17 roses. Hope this is of some help.

new at this just checking out your site because of a friend in Michigan

Hello from Ontario
I have had pretty good success with DA roses (Wenlock, Golden Celebration, Tradescant, Abe Darby, Kathryn Morley, Gertrude Jekyll). I think mine are all grafted. Protecting them from winter is key as Stargazer5b said, I sometimes out of laziness, cut back to about a foot, throw some mulch eg compost around the base and cover with an old blanket held down with a couple of small rocks. Some of my DA roses have survived 6 winters this way. Uncover when the forsythia is in bloom, ie ground is warm enough. Enjoy!
Mary Anne