Wow! Wow! Meooow!  If your cat likes catnip, these buds are going to be a real treat! The flower bud is the most potent part of the nepeta cataria catnip plant containing the most concentrated amount of nepetalactone (that is what makes kitty get all silly). 
 
We recommend pinching and rolling the bud between your fingers to release the oils and letting your cat roll around and summersault in the tiny flowers. You can also give a whole bud to your cat to play with but removing any stems as they appear is always a good idea. (Cats can be like kids and find it interesting to stick things up their noses... When I was a kid one of our cats sniffed up a burr. I'm pretty sure kitty would like to keep vet trips to a minimum.)