Henley Flowers buttonholes are usually made with integrated pin fixings
(so that they can be put on like a badge).
For anyone wearing a delicate fabric, they can also be made on magnets. Or for something a bit different, why not opt for a wrist corsage or handbag corsage.
See below for lots of examples:
Can be made with silk/artificial flowers (as pictured here), not just using fresh flowers.