Mums Will Do Too
Stop and Smell a Rose Day refers, of course, to the old adage that means you should take time once in a while for the nice things in life.
This assumes you'll be able to find any.
Celebrating this day also assumes you'll be able to find some roses. They aren't all that easy to find. Not that many people grow them. If you don't grow them yourself, you could look a little strange going around and smelling other people's roses, especially since you'd probably have to go into their backyard to get close to them.
You probably could stop in at a greenhouse or a flower shop or grocery store and find some to smell.
As the subheading above suggests, you can substitute mums (i.e., chrysanthemums) in a pinch.
Other flowers will just have to wait for their own special day.
I don't know of any restriction as to the color of the rose you smell. It's probably best to find some that florists haven't purpose dyed another color though. There's just something wrong about that.