As I prepare my mechanics for this DIY boutonniere, I tape a few florist wires with white floral tape to use as hairpin braces. (These are used to hold the leaves against the rose).
Bend the wire in a hairpin shape and place against the back of the taller leaves.
Keep in place by taping the stem of the wire against the Dusty Miller leaf stem.
When finished, the wired back helps hold the leaf erect and will better compliment the finished boutonniere.
Place the wired leaf behind the rose head, edging it above the top of the wired rose.