Everyday a group of robins come when I’m away at work and either step on or peck on my calla palustris(bog arums). They break off some of the stems and chew the tips of the growth. Is there any way to stop this? I can’t put a fence around it as they are scattered throughout the pond and if I do they will become rusted in the water. Do I just have to live with this just praying they won’t completely kill my plants?