My wife and her friend Jen run the online celebration and gifting magazine, Pimlico. They are finishing the final shoots for the Holiday/Winter issue, and one of them required a flower arrangement. Since they are on a budget, the only flowers purchased were a dozen of peach roses from the local grocery store. All the other greenery and flowers came from our garden at home or around the nursery at work. Below is the almost final arrangement (Black sweet potato vine will be added fresh for the shoot since it will wilt between now and then.) I think this is a great example of how to use what you have at hand in the backyard to make a unique arrangement, even outside the peak of spring and summer flowers.
The other benefit of looking to your own yard for greens and flowers are the different textures you would not normally be able to pick up yourself at the florist or would think to request in an ordered arrangement. Look for the Holiday/winter issue of Pimlico for the finished arrangement. In the mean time here is a breakdown of the flowers and greenery used: