I love the look of fresh ivy when making a boutonniere. Choose the smaller, daintier leaves that are proportionate to the size of the flower head.
You can tape the stems of the ivy directly to the corsage, but - again - I like the control that wiring each stem of greenery gives me. It only takes a few seconds and a bit of corsage tape.
Hook the wire into a hairpin shape and pull down over a lateral of the ivy and then tape securely.
Now the stem is slender, easy to manage and can be bent to go in the direction you want.
Leafshine is a product used by professional florists to seal greenery and plants. It seals the greens, cleans up any spotty residue left by the flower bath and helps keep the leaves fresh.
It dries to a pleasing glossy finish that looks beautiful in all arrangements, corsages and boutonniere work. I have both larger cans (as used in professional shops) and smaller cans good for a single event use available in my online store.