This border is a lot simpler than it looks and is done all in one...you work over the arches with single crochets and picots. This border is adapted from a vintage lace edging, I hope to do a tutorial on that soon.
Please see my previous tutorials for the blanket/cushion tutorials.
https://youtu.be/5WZM5rkLjqA
https://youtu.be/fcXACbE_8_Y central rosebud motif
https://youtu.be/P78iIjoEt3Y lace around central rosebud motif
https://youtu.be/L2ZTYPkPvNA outer rosebud border on square