Simple and Sweet Floral Arrangement

Since I will be arranging all of our bouquets and centerpieces myself, I would like to keep them as simple and inexpensive as possible. The only caveat to that is that I want real flowers - not dried or silk. I love this look for its simplicity. My grandmother has a ton of clear Mason jars and a few green ones like the one above. However, she also has crystal vases and bowls and around 5 different pieces of milk glass containers.

How can I translate this look for a fall wedding? Lilacs don't bloom in October ;) 
photo via {Oh So Beautiful! Paper}