Paeonia broteri grows wild in Portugal and Spain. If you’re looking for seeds from nature you can order them from the Portuguese seed company Sementes Vivas. They are located close to a natural population in Touloes, Idanha-a-nova close to the border with Spain in the middle of Portugal. It is known there as Rosa Albardeira and the company is involved in an effort to increase the natural population. In this video they show how to sow them, it’s in Portuguese alas, so hard to understand, but what is striking is that they remove part of the seed coat so that the embryo can get through it more easy. I wonder whether that makes much difference but is worth experimenting with I think. If anybody would have some experience with this method I’m interested to hear what kind of results you had .