A plant that provides oxygen to its surroundings is good for ground ventilation and therefore good for other plants. Black bog-rush is such a plant. It also absorbs calcium, which it releases when its leaves die off. This is why the places where black bog-rush grows are favorable for other plants to germinate. Black bog-rush grows in thick clusters and is easy to recognize by its dark flattened button-like 'flower' standing at the tip of its stem. Rabbits like to nibble on the leaves and it is a host plant for various moths and flies.