For the past three years I've been protecting my seemingly-overeager tree peony, which often begins unfurling its leaf buds as early as February here along the New Jersey shore. Well, this year the protective "tipi" materials were just too far buried in the shed and I had to let it fend for itself, swelling flower buds and all, through temps similar to yours .... and it's looking just fine.

When I think of the time and effort I'd been spending, removing the tipi on sunny days, replacing it before cold nights, putting water-filled jugs in there to help stave off the cold ...

FYI, the variety I have is 'Feng Dan', growing in a well-amended but basically very sandy soil in part shade. The flower buds may not be as far along as yours; they're just a bit larger than my thumbnail - about 3/4" long, but it's definitely broken dormancy. Keep in mind that some varieties may be more cold-hardy than others.

Diane

Down to about 20F if in leaf stage fairly safe for tp's. If becomes colder cover up lightly with cheap sheets. The 7F we had last Easter was too cold and killed most of the buds. If you have room plant in a place that is in shade until later in the season, such as north side of house.

Thanks to both of you for your help - I won't panic about this, given your experiences. Now if I could just figure out how to protect the Bletillas and Arisaemas that insist on breaking dormancy so early...

In all the years I've grown tree peonies(41) I have only had buds freeze once. It was Shimadaijin. Herbaceous is another story.