Floral foam
A green plastic foam that soaks up water and holds cut stems in place in an arrangement.
Also: oasis, florist foam
Floral foam is a light, brittle block that absorbs many times its weight in water. Stems pushed into it stay where they are put and can drink, which made new shapes of arrangement easy. It was developed in the United States in the 1950s and is widely known by the brand name Oasis. Standard foam is a plastic. It does not rot and breaks into tiny particles, so many florists now avoid it and use chicken wire, pin holders, moss or reusable cages.