Floral foam is widely used because it’s extremely useful. By anchoring flower stems in it, florists can build enormous and sometimes gravity-defying arrangements. The foam also soaks up water which improves the longevity of the flowers. The problem is the foam has a longevity of its own. Plastic takes hundreds of years to break down – some experts even suggest they may not break down at all in landfill. If you put the foam in the bin, that is where it will end up, and likely stay. 
But many florists put the foam down the sink, according to Melbourne florist Rita Feldmann.
University of Adelaide molecular pharmacologist Dr Ian Musgrave said like putting any plastic in the waterstream, washing away floral foam was a bad idea. "I would not flush it down the sink," he said. "It’s probably not going to be very toxic, but you’re just adding more inert materials to the waterstream which can potentially have averse effects. Not because they are toxic, but organisms can eat this stuff." 
Florist Rita Feldmann is concerned about the impact of the widely used floral foam on the environment. Ms Feldmann and a growing number of florists, congregating around the Instagram account @nofloralfoam, are concerned about the health and environmental impacts of the foam - which is used in enormous quantities every year, and then promptly thrown out. "It’s everywhere. You go to a supermarket, grab a block of flowers, it’s in the bottom. At races, weddings, it’s all foam," she said.
Air is then added to turn it into foam. That foam is treated with detergents to give it the unique ability to soak up water. The foam is made with two toxic chemicals, but is not necessarily harmful. There is almost no phenol or formaldehyde left in the finished product – less than 0.1 per cent of each chemical.
