The grass tree has a symbiosis relationship with Mycorrhiza deep in its root system. Mycorrhiza is fungi that live in a mutually beneficial relationship with the grass tree roots. The fungus increases the tree root’s access to water and nutrients and therefore increases tree growth especially in poor conditions. The grass tree also suffers from a condition known as phytophthera dieback. "Phytophthora cinnamomi" is a discrete soil borne pathogen that attacks and destroys vascular root systems, causing hosts to perish through lack of nutrients and water. It is spread through infected plants and the movement of contaminated soil and gravel.