Hi katy This is my first season ever to contend with extra large blooms. So I'm only sharing what I've done 'till present: I stick a fine stake near the blooming cane and then tie up the open flower just below the pedicel to it. Once done, after deadheading I pull out the stake. Yours look like a DA English shrub that tend to have drooping/down nodding blooms. In some of my hybrid teas, they have put out very sturdy canes that may not even need propping because the bloom atop is still kept in place in spite of their extra large size.
What is changing in our planet that is causing this is a mystery to me...
Arturo