1. Creative bosses don't drive creativity
Creativity is more like curling than golf. You don't try to drive the ball, you make room for it to slightly change direction, and you have very little control over it. Even if it drives you crazy. Creative bosses don't try to force their employees to be creative. It doesn't work. They don't even try to give their employees 20% of their time to be creative, or build an innovation lab for them, because those don't work either. Instead, creative bosses allow their employees to innovate naturally and individually. See next point.
2. Creative bosses embrace your failures.
Some of the best ideas come out of trial and error. The Marshmallow challenge focuses on how to experiment as early as possible. While you can argue with the virtue of praising failure, "Fail Fast, Fail Often" suggests experimenting as much as possible. Sometimes you don't have the perfect formula, but once you experiment, you can improve and reach the desired outcome. So what separates a creative boss from a not-so-much one? How they respond when you go to them and tell them: "I tried something you haven't authorized and failed." The uncreative boss will make it clear that you made a bad career choice. There will be personal consequences for you. This might go in your personnel file. And a creative boss? She will ask: "so, what have we learned from it?" or: "what's your next move?" or suggest a few people in the organization to consult with. She will not celebrate failure, but she will make it clear that failure is the unnecessary part of success, and as your boss--she has your back even when you fail.
3. Creative bosses ask: what do you need?
What happens when you come to your boss with a great idea for the organization? A mediocre boss will "take it from here." Often they will put it in a stack. Or under a stack. They are not as passionate as you are about your idea, and that's OK, but it will discourage you. One of the worst experiences I had was when I came to see my boss with what I believed was a great idea for a next product and he, although not dismissing it, told me he will pass it on to the team that will (or will not) continue the development. I was completely out of the loop because that "wasn't my job." A great, creative boss will ask: "what do you need to make this happen?" Doesn't matter that it is not part of your day job. It doesn't even have to come at the expense of your day job. He will let you figure out how good this idea really is. He will put you to the test to see if you're passionate enough actually do something to make it happen.
4. Creative bosses tell you what will make them say yes
A great boss will tell you what you need to bring for her to say "yes" and give you what you needed to take your idea all the way. My study showed that one of the most powerful motivations for employee creativity is the visibility to the "big picture." Bosses tend to believe that their world is past the comprehension of the "simple" people. Well, it is not. Letting you "walk a mile in their shoes" and sharing how they make decisions and what constraints they are subject to will not only empower you, but will also make you understand the impact of your own project on the company--yet another factor that positively affects your creativity. Once, as a General Manager for a $100m business unit at Texas Instruments, I worked with an account manager for one of our biggest customers (Hint: Apple...) It is a well-known practice that general managers do not share cost and profit margin numbers with their sales people. The standard practice is that you give your sales manager a price to hold. Once the customer applies more pressure, they call you, and you make the final decision, which will likely be a price lower than the price you gave your sales manager as your "final". Everybody knows that, including the sales manager and the customer. So they all play the game. But I trusted that sales manager, and instead of giving her a price (knowing I can afford a lower price), I told her exactly what my cost was, what my cost reduction plan was, and what was the gross margin at which my boss will make my life miserable. She negotiated with the customer and got me a price that will give a better margin than I gave her.
Everything described here about your boss also applies to you, if you have employees reporting to you. Are you a creative boss?