I'm thinking I've got RRD. Whaa. Last year one plant had witches broom in two spots. I had been using roundup to control some pernicious vines under it from time to time, and read that could cause it. But now there's witches broom on all the plants in the group. No excessive thorns, or extra long canes. I figure that it must be RRD for it to spread. Wisht I'd got rid of it last year.
I don't know what rose it is. It was ancient when we moved in nine years ago. There's a link below I posted a while back, but no one identified it. In the spring flush, the clusters have 50-100 roses. I tried to estimate once how many at full flush and came up with about 50,000 roses -- I can't tell you how accurate I am, though. The group is about 15 feet across. Too bad I can't wait until they bloom, but as I understand it, I need to take them out now.
Here is a link that might be useful: Unknown white rose