Paeonia humilis, also classified as a dwarf subspecies humilis of the Apothecarie's Peony Paeonia officinalis, is just coming up in the display bed next to the Fern-leaf peony. But it was just transplanted here last fall from the open field, so it may normally be earlier.
And also in the display, a.k.a. datum, beds the Siberian Paeonia obovata is just now starting to shoot. It looks decidedly weird surrounded by 2-ft tall peonies in full leaf and ready to flower! The shoot on the right already has a small flower bud sitting on it.
Meanwhile beside P. mascula the somewhat similar Paeonia ruprechtiana has opened today.
This species ranges from SE Europe to the Caucasus. My plants are from seed reportedly (3rd hand) wild collected in the SW of the Republic of Georgia (Not Georgia USA, but over in the Caucasus region.) Its' natural environment is woodlands and mountainsides in the subalpine zone and lower. Here it is equally vigorous in part shade as in my woods; I don't have any in the open field.
I'm using the name on the label the seed arrived with. Distinctions between some of these very similar species and subsp are often beyond my ability effectively to apply the botanical descriptions of the books to the actual plant sitting in front of me.