In my travels throughout the South I’ve been fascinated by the Spanish moss that drapes the branches of many trees, notably live oaks and crepe myrtles. Spanish moss (Tillandsia usneoides) belongs to a large genus of about 550, mostly epiphytic, species in the bromeliad family (Bromeliaceae). Spanish moss (USDA zones 8-11) is native from the southern U.S. (southeast Virginia to Florida and west to Texas and Mexico). This “air plant” lacks roots, relying almost entirely on atmospheric moisture and rainfall for sustenance. The limbs of its host tree (or telephone wire or clothesline) serve only to provide support.
The long, slender grayish-green stems and leaves of Spanish moss can reach 20 feet. They are covered are covered with dense trichomes that act like reservoirs to capture moisture and nutrients.
Three-petaled pale blue or chartreuse flowers are borne singly in the leaf axils in late spring and early summer and are pollinated by moths drawn to the musky fragrance. The small fruit capsules that result, split when ripe to release seeds that are outfitted with silky hairs. Dispersal is mainly by wind. Reproduction also occurs by vegetative offsets that are broken off and transported by wind or animals.
Historically, Spanish moss has been harvested and baled for use as livestock feed, garden mulch, mortar reinforcement, packing material, and mattress stuffing. It was also used as stuffing in the seats of Henry Ford’s Model-T cars.
Visitors seeing live oak trees heavily draped with Spanish moss frequently ask if the plants are harming the tree. While Spanish moss is not a parasite in the way that mistletoe is, it can affect its host in a number of ways. First, there is the shear weight of the moss which can sometimes cause weak limbs to break. A subtler effect has been termed nutrient piracy. By intercepting wind and rain-borne dust before it can reach the ground, Spanish moss may capture nutrients that might otherwise go to feed the host plant. Such a cost is a minor one, however, and not a reason to worry about the Spanish moss that gives the Deep South so much of it’s character.