Spanish moss (Tillandsia usneoides) is not a moss but rather a member of the bromeliad family and a distant relative of the pineapple. It is also not Spanish; Frenchmen in early North America named the plant after the long beards of their rivals, the Spanish explorers. Spanish moss is not parasitic like mistletoe and is a true epiphyte, or air-plant. Spanish moss prefers growing on trees in alkaline soil, where trees may absorb and shed excess minerals that feed the ghostly, trailing plant. Although its days as packing material and upholstery filling are over, no scene set in the Deep South is complete without the evocative appearance of Spanish moss.
Bald cypress (Taxodium distichum) trees resemble conifers, with needle-like leaves and a conical form. However, bald cypress drop their leaves in the fall, like broad-leaved deciduous trees. Bald cypress are very long lived, thriving for 600 years or more. These are the symbolic trees of the wetlands, with knobby "knees," or conical extensions from the trunk. Bald cypress can grow 100 to 150 feet tall. Because both bald cypress and Spanish moss thrive in humid, wet and tropical areas, they have become inseparable in stereotypical swamp scenes. Spanish moss also prefers bald cypress due to the horizontal branching structure.
Southern Live Oak
Southern live oaks (Quercus virginiana) are broad and spreading trees, providing plenty of horizontal surfaces for Spanish moss. Although they grow 60 to 80 feet tall, their width can reach 120 feet. Like bald cypress, live oak trees live for centuries in the right conditions. The University of South Carolina theorizes that live oak leaves shed excess minerals, giving Spanish moss an extra boost. This, combined with live oaks' long life, encourages Spanish moss. However, heavy growths of Spanish moss prevent sunlight from reaching lower branches and stress the host trees.
The rough, corky bark of the hackberry (Celtis occidentalis) allows Spanish moss seeds to sprout and gain a foothold. The 2- to 3-inch leaves allow sunlight to reach the epiphyte, and the broad branch structure supports the trailing plant. However, hackberry trees are susceptible to limb breakage if they are not pruned for limb strength in the first decade of growth. These deciduous trees grow throughout the continental United States and, once established, grow in poor conditions, including drought, compacted soil and pollution.