You have all the time to rearrange or polish your flower arrangement. The flower design should look beautiful and artistic enough before you place your filler, when the filler is already placed, it would be harder to move your things around the area or place. Bear in mind that The filler are very fragile.
It is said that the practice of flower arranging was originally used in Japan to pay tribute to the gods, and the floral arrangements were therefore considered sacred. In Japan, historical records documenting the appearance of traditional flower arrangements date back to about 500 years ago. It was in the seventeenth century that followers of this new form of artistic expression started creating the rules leading to the formation of what would eventually become the disciplinary art that is now known as Ikebana. The diversity of forms and methods that were developed over time made Ikebana a much more sophisticated form of art. In the end, Ikebana has become a discipline where the stage for the artistic expression is set by the harmony achieved through the combination of natural materials (flowers, stems and branches), the container, and the lines and forms that characterize the art of Japanese flower arrangement.