This year (2019) the prize for the first peony to bloom in the entire MBGNA peony collection (tree or herbaceous peony) goes to the herbaceous peony 'Smouthii'
It should be noted that this same peony (new to the collection in 2017) bloomed in 2017 on May 6, 12 days earlier than it did this year, and 2017 was fairly typical for its blooming period (neither especially early, nor late.) This will give you some idea of just how late this year's spring blooming season is. After a long hard winter, temperatures have remained at or below normal for the most part.
Bed 23 Smouthii (3ef)
Peony Garden at Nichols Arboretum
Taken May 18, 2019
I can't tell if the "prize" is in your wheelhouse or if there is a real prize at the gardens for the first bloomer. Great shot of this very pretty red one. We are having a much cooler spring here than usual, tho not a cool as yours!