Arranging flower bouquets is not unlike gardening. Would you plant a mess of random seeds that don't go together logically, like roses, wildflowers, and tulips? Of course not, so why would you arrange a bouquet that way?
The goal in any type of flower arrangement, whether it be in a vase or in a yard, is to follow the rules. Arranging flowers is an art form and, in order to be successful at it, you must adhere to the design principles and elements. These principles and elements include balance, harmony, unity, and rhythm.