Ball moss (Tillandsia recurvata) is a harmless epiphyte - a plant that grows on the surface of other things. Ball moss absorbs water and nitrogen from the atmosphere and is in no way parasitic.
When looked for, ball moss can be found growing on electric wires, screen doors, wooden fences, and numerous other places in the environment.
Ball moss prefers both shade and high moisture - both of which can be found beneath a tree. As trees grow, low limbs follow a normal pattern of mortality. As the shade increases, low limbs die providing the ball moss an ideal place to reside. Many folks will look at a dead or dying limb in the lower portion of a tree's canopy and jump to conclusion that it was killed by ball moss. The lack of sunlight penetrating the canopy is the most likely reason for the limb to have died and becomes the preferred place for the ball moss to live.
Ball moss takes up to 3 years to mature. Once mature, it will bloom for the next 6 or 7 years. The flower of the ball moss is incredibly small with single purple petal. Once pollinated each flower can produce 70 to 100 seeds with as many as 50 to 60 flowers per mature clump of ball moss. While flowering occurs mostly during the spring, ball moss can be found flowering most any time of the growing season. The seeds dispersed by the dried flowers resemble those of the common dandelion. As small bits of white fluff, they are carried from tree to tree by the wind.
As wind blows over the top of a tree, a slight updraft is created beneath the tree. This aids the ball moss seed to move up into a tree. Ball moss is found most often on the bottoms of limbs partly because of the way the seeds are deposited.
Ball moss in no way indicates a tree's overall health or general well-being. Instead, all it does is indicate the presence of more ball moss. Heavily infested trees are generally found near bodies of water where the ball moss can benefit from the higher relative humidity. Along streams, creeks, and lakes, (even small ponds), one finds a greater incidence of ball moss.
The fluffy seed of the ball moss adheres best to rough barked trees. While possible, it is less frequently seen on smooth barked trees such as crape myrtle or sycamore. In addition, trees that regularly shed large pieces of bark such as pecans seldom have large infestations of ball moss. Oaks, with their roughly textured and thick bark, provide a very good surface for the seed to adhere. Typically hanging onto dead limbs for 15 or 20 years or more, oaks make a good place for ball moss to live and proliferate.
Controlling ball moss isn't easy. While it is possible to physically remove more than 95% of the moss from a single tree, removal of the seed left by the ball moss is impractical if not impossible. Ball moss on neighboring trees will release seed and re-infest the tree in a short period. Spraying is often touted as a cure but is not a very satisfying remedy. Three sprays are routinely used - a concentrate of sodium bicarbonate (baking soda), potassium bicarbonate, and copper hydroxide (Kocide®). Each product is a chemical salt capable of killing the ball moss. The salts work by desiccation - drying out the ball moss - and therefore killing it. Ball moss starts as a minuscule plant until at maturity it weighs just a few grams. Most of its weight is water held within the plant. When desiccated, its weight can be reduced as much as 90%. Then the dead ball moss continues to hang in the tree for 8 to 10 years in oaks, less in other trees.
Pruning a tree correctly removing the dead and dying or broken limbs typically will remove 60 to 75% of the ball moss. Pruning - the physical removal of the ball moss - is the best way to significantly reduce the problem. Regular pruning that includes the removal of dead or dying branches significantly reduces the amount of ball moss.
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