Jim,

If you are worried about the sprig drying out (and if there is room behind your cap badge) you could do what I do when I wear a boutonniere. Make a very clean cut at an angle along the base of the twig and set it in a small amount of water even better cut with sharp scissors at an angle under water). Cut a small piece of aluminum foil and a smaller square out of a paper towel. Moisten the piece of paper towel. Remove the spring from the water and wrap the end with it with the moist piece of paper towel. Then put the end on the middele of your square of the foil. Fold all the edges up and mold the foil to be as compact as you can without bruising the plant. The moisture of the towel should keep the sprig fresh and the foil will keep the moist paper towel from drying out and prevent the moisture from staining your hat.

Cheers

Panache