Looks a lot like Margaret Merrill to me.

Jen

6 inches wide bloom implies an HT--Margaret Merrill never had large flowers for me. What's the fragrance like and does it have a lot of thorns? Have a look at the flowers again later in the summer--as the plant settles in it may have more of an HT form and may be easier to ID.

With a flower that big it sure reminds me of Queen Elizabeth. There is a white sport of QE, but some of the pictures at HMF show some blush at the center. I don't know, just a thought.

Here is a link that might be useful: White QE at HMF

Here's more info. It has a very very slight fragrance that you can only smell if you put your nose close to the flower. The almost opened flower has 18 petals, and the opening one has 22. The new growth (stem) has some thorns but not too much.

If I remember right, together with those batches of bagged roses that came in with this rose is a JFK but I didn't want a white...I wanted a Gene Boerner!!! Looking at Help me Find though says that JFK has a strong fragrance, this rose does not have that. The pic looks very much like it though.