It's not super rustic and I don't know about the bow/flower thingy... But the idea for a card holder is good. You could use a galvanized bucket with a chalkboard or something. I think I pinned something like that for you.
5" Burlap and Lace Bow - Rustic Wedding Bow - Handmade Lace Bow - Woodland Rustic Barn Wedding Decorations