To make flowers arranged in a vase keep long by containing an additive for giving activity to natural flowers in a frog base.

The foamed frog 1 for flower arrangement is made by a phenol foaming body having open cells (a)..., and an additive 3 for giving activity and nutrition is contained in the frog base 2 for supporting flowers (b) arranged in a vase. As a containing method, for example, in an indirect mixing method, the additive 3 is, preferably, granular with the maximum mean diameter of 0.5-2.0mm, and the additive is mixed with a phenol resin and heat-molded with a hardening agent or a foaming agent. The maximum mean diameter of the granular additive 3 is made larger than the maximum mean diameter (0.3-3.0mm) of the section of the cell (a), so that the additive 3 can be prevented from flowing out early to make the effect keep long. The additive 3 is an activator, a nutrient agent, germicidal, and antibacterial disinfectant or the like.