Moss Growth on a Live Oak Branch

Habitat

• Spanish and ball moss prefer moist habitats, near rivers, lakes, ponds and wetlands, but they can also be found away from water where humidity is sufficiently high. They will grow on deciduous and evergreen trees, as well as on broad- and needle-leaf trees alike. In general, both plants prefer trees with a lot of branches and rough bark. They are perhaps most prevalent on trees that have a lot of horizontal branches to accommodate their hanging, such as live oaks and hackberry trees. Both Spanish and ball moss thrive in partial shade. In general, their presence is commonly associated with trees in poor health.

Reproduction and Spread

• Spanish and ball moss reproduce either by seed or vegetative division. Seed dispersal occurs from December through March. Plants require only moisture and temperatures of 60 degrees Fahrenheit and warmer. Seeds will germinate after becoming affixed to a suitable host. New plants may also grow from broken-off pieces of other plants. Strong winds readily divide and spread long strands of Spanish moss. Severe storms are known to accelerate its spread.

Inter-Species Relationship

• Spanish and ball moss have little effect on their host trees. They are not parasitic plants, and they use live oaks strictly for protection and support. Both forms of moss are most prevalent on declining tree specimens, but the tree's decline is due to other causes. It is possible that very severe moss infestations can contribute to further tree decline by shading out tree leaves, discouraging new shoot production and causing weak branches to break from additional weight. Overall, the biggest impact is aesthetic. Control is possible, but it tends to be difficult and costly.

Control

• Restoring tree health and vigor will reduce the prevalence of Spanish and ball moss, but first you must determine the cause of decline. Mechanical removal, by hand or high-pressure cool water spray, will also effectively eliminate some of the epiphytic plant growth. For larger trees, specialized equipment like cherry-pickers may be necessary. Carefully remove clumps. Damage from firmly grafted moss can lead to more serious fungus infections. You may also consider using fungicides containing copper, but be advised that these chemicals can negatively impact tender new growth on live oaks and on surrounding plants.