I have seen a number of Laxas. I am not interested in the root stock but the rosa the is one in Suzanna. The options are Rosa corymbifera and plain R. laxa which is the one
Your wording is slightly difficult to follow (although you do great with english as a second language). Helpmefind claims the parent of Suzanne is R. laxa:
…hope that helps.
The R laxa that you want is shown in helpmefind only if you pay for the lineage function I think, except if a 1st generation hybrid for which parents may be listed. Suzanne is from the wild species with pale flowers, that grows tall.
There are a bunch of roses loosely labeled “Laxa”, as rootstock. Some are corymbifera as you indicated. Others have a variety of different species, subspecies and cultivar names. They are different kinds of Rosa canina and related types. One I recently looked at a paper on germination properties of was Pollmeriana, used in the Czech Republic for instance.
Hugh Skinner does have the original R. laxa and may have time to do some more things with plants now that his Mother has passed.
I have it from him and the rebloom is consistant and it’s a healthy plant.
I called him, rather than emailed him, FWIW.