I have noticed that western style gardens _ such as those seen in big castles, for example _ characterize themselves by man_made forms that generally follow symmetric patterns. In contrast, Japanese gardens, while also man_made, always try to recreate lifelike landscapes, by using not only botanical elements but also water, gravel, rocks and other natural components. In a similar manner, when compared to western floral arrangements, Ikebana compositions also have a stronger emphasis in reproducing natural settings.
You could create an arrangement for any size vase, the larger the vase, the more flowers and greens to use. For Christmas time, use red, white and maybe even green flowers (like green button mums). Also choose from a variety of greens and evergreens out there. Accent a red rose in a bud vase with some baby's breath and cedar. Deep red alstroemeria are especially beautiful. There are many other flowers that would be perfect to use for Christmas arrangements, the link below will take you to a complete list of flowers, foliage, and evergreens for Christmas floral design.