Does the spanish moss plant hurt the tree it grows on? Probably not. As an epiphyte, spanish moss does not infiltrate the tissues of its host tree, as a parasite plant would. Epiphytes get most of their nutrients from the air. Spanish moss plants have no roots. The long strands of the plant (which are basically leaves) curl around tree branches and cling to bark textures. There is an argument that if spanish moss is hanging very thickly from tree branches, it is cutting off some of the light from the tree’s own leaves. On the other hand, if you see a tree in obvious decline with the spanish moss hanging very thickly from it, it’s likely that the spanish moss increased its growth only after the tree’s outer branches and foliage started dying off for reasons unrelated to the spanish moss. Most experts advise you not to worry about the spanish moss – it is just hanging on the tree, not hurting it. However, there are pecan farmers who clear heavy spanish moss growth off their crop trees. Very thick spanish moss accumulation can be heavy enough to break a tree branch, especially after rains, when spanish moss plants absorb several times their weight in water.
When there are long periods between rains, spanish moss can go dormant. It does have flowers, and they are usually quite small. Water and other nutrients are taken into the plant through scales on the outer surface of the leaves. Spanish moss usually spreads to new locations via tiny seeds. Each seed is attached to a small puff of lightweight fibers, which makes it float on wind currents.
Various kinds of animals use thick areas of spanish moss as a shelter – bats, reptiles, amphibians. Some birds build nests with it. There is a jumping spider (Pelegrina tillandsiae) whose only habitat is spanish moss.
But what about chiggers? Have you ever been advised not to touch spanish moss because chiggers will come out of it and bite you? The most scientific advice I could find says that you should only fear getting a chigger attack from collecting spanish moss off the ground. Spanish moss hanging from trees should be chigger-free. But it might not be free of jumping spiders, bats, and snakes!
For information on visiting Phinizy Swamp, see: http://phinizycenter.org/