This is the post bloom mind you, the finished flower.
I'm thinking this is Hydrangea paniculata 'Pink Diamond' and that it will need some pins to stake a few of the lower branches into the ground under the mulch. Next fall those newly rooted pieces can follow me home.
That wasn't the only hydrangea in full post bloom on the last day of September. I went to collect lily seeds and have a jar of them saved. What caught my attention was the hydrangeas. This is another H. paniculata cultivar.
I have plenty of the native H. arborescens and have planted a couple of rooted cuttings of the H. paniculata and several Oakleaf Hydrangea in the garden to be. I have easy access to H. arborescens 'Annabelle' whenever the time permits to transplant some.
Can I have too many hydrangeas? I think there is plenty room for more.