I have the same experience with these two roses in my garden. Kathleen Harrop and Zephirine Drouhin grew side by side ... same soil, exposure, and care. ZD was prone to blackspot and was leafless by July, even with fairly spotty application of systemic fungicide. KH is nearly disease free with the same spray schedule, and it blooms more than ZD ever did. ZD is long gone, because I grew weary of her underperformance. KH is still here, and I am very happy with it.

My family has grown GD for at least 75 years, since my mom, when she about 10 (and is now 86), was given a cutting from a neighbor's plant. She stuck it in the ground at the end of the porch of her childhood home, and it proceeded to climb up the post and across the porch roof. It is glorious in full bloom. It was one of the reasons I fell in love with roses. It has always bloomed in time for Mother's Day here in E.TN. When I moved out, I took cuttings with me, and have grown it ever since. But in all the years of my life (62, so far), I've seen exactly three blooms anytime other than the Spring flush: once a single bloom, another time, two at once. In both instances, it was during a prolonged, open Fall season, with cool nights, warm days, and late frost. So, to make a short story long...no, GD is not remontant, but once in a great while you might be blessed with a single out-of-season bloom.

John