Spanish Moss despite its name is not a moss at all, but a Bromeliad, a perennial herb in the pineapple family. Spanish Moss are epiphytes. Epiphytes grow on other plants but do not rely on their nutrients. They take nutrients from the air and debris that collects on the plant. Spanish Moss has permeable scales which catch moisture and debris/nutrients. Spanish Moss prefers moist environments, but its ability to collect water lets it survive during dry conditions. It attaches itself by wrapping around a plant surface. Many homeowners think Spanish Moss will kill their tree, this is not the case because moss is not a parasitic. It uses the trees for support. If you notice a decline in a tree after Spanish Moss has infested it, its usually declining for another reason. A thining tree canopy due to stress of any kind will actually cause moss to grow due to the added sunlight. Heavy moss can slow tree growth by shading the leaves, but a healthy tree will grow faster than the moss. Moss can be removed, but it will eventually grow back.