This is a lovely trend that I'm seeing more and more of; special family keepsakes or heirlooms hidden or attached to bouquet. For my own bouquet I had a yellow rose inserted into all the flowers to commemorate my grandmother as it was her favourite flower. Your own can be a memory to someone, a family heirloom, or a badge that symbolises something about you and your other half. I've seen pictures in lockets, old military badges, and grandmother rings. It's perfect too for the "something old, something borrowed" wedding tradition.
Are you having something like this at your wedding?
Here are some more ideas of what you can do:
A bouquet tie with a special meaning. Perhaps a piece of material from your mum or grandmother's wedding dress could be used to tie around your bouquet.
Pet tribute. If you've lost a pet then you will understand how hard it is, especially if you'd planned to have them at your wedding day. You can use their collar for your bouquet or something made specially with a picture of them.
A charm. You could have a charm made or a pendant engraved with your initials and wedding date, then use it later on for a necklace.