It sounds an awful like you have a Dr Huey sucker coming from the rootstock. Even if it were to be a mutation/sport you wouldn't have a true WBY, since Grande Dame is the product of sexual reproduction and therefore has a blending of attributes from its parents. Any sport would be a completely new rose, though based on the DNA of Grande Dame.

The good Dr is considerably darker than Wild Blue Yonder, more of a blood red, but the flower form is similar. Are those new canes *fairly* thornless compared to Grande Dame? The fact that it seems to be a once-bloomer is another clue. See if this looks like your mystery rose: Dr Huey

Did you take any pictures? WBY looks lavender/purple in pics on HMF, whereas Dr. Huey is definitely RED. I agree that it could not have actually been WBY, but what actual color was it? It could have been rootstock (most modern roses are grafted onto another roses' roots to make them grow faster), or it could have been a sport (natural mutation - usually just to a different color).

Not all rootstocks are Dr. Huey, so it could still have been a once blooming rootstock, but a different rose from Dr. Huey. I had an amazing rootstock come up once on a rose which was in our garden when we moved in which I actually did not like. The rootstock was once blooming, but it is one of the most beautiful roses I had ever seen, and it is magnificently fragrant. I kept it. Turns out its name was 'de la Grifferaie' (Vibert, 1845) - here is a pic of it from last Spring.

Jackie

Thank you both for your comments. I am still learning alot! I did not take a picture. I wish I had, but the rose looked ALOT like the picture of Dr. Huey that fig_insanity sent. I feel pretty certain that is what it is. I think I will sp it, and replace it now that I know it is not Wild Blue Yonder. It was a fun learning experience.