Ball moss is not a moss at all and it won't harm trees


April 12, 2007




While driving through the countryside in the Mission Valley area, one tends to notice trees that have funny stuff growing on the branches. I've also seen it in yards in town and acreage in rural areas. You notice it more in the fall and winter when the trees have lost their leaves. If you live in one of these areas you know what this funny stuff is - ball moss. Most often seen in southern Texas, it can be spread to any part of the state on transplanted trees.



Ball moss is not really a moss at all. It is a member of the bromeliad plant family. It is a grayish-green pincushion-like growth that has its own seed and flowers and grows on other plants such as tree limbs, but does not take nutrients or water from them.




Ball moss (Tillandsia recurvata) is not a moss at all. It is the grayish-green pincushion-like or tufted growth seen on the bark of a number of Texas shade trees. It is a true plant with seed and flowers. Ball moss is a member of the bromeliad family and is related to, believe it or not, the pineapple.


Contrary to what most people think, ball moss is not a parasite. It is an epiphyte. This means that it grows on other plants, but does not take nutrients or water from them. It manufactures its own food from nutrients and moisture from the air. You see it on electrical wires, barbwire fences and barns. Homeowners are most concerned when it is in their trees. In some cases, it is hard to tell if some of the larger balls are one plant or several of them.


Small seeds from the ball moss are produced on a slender stalk within a capsule. The stalk extends above the bunchy plant growth. When the capsule opens at maturity the seeds are released into the air. They are carried by wind to the rough older bark of the tree and stick to the surface and germinate. As they develop, "hold fasts," or false roots, start to form to hold to the structure.


Ball moss is most often found on the interior branches of older trees, like the one above. This tree is likely in decline due to environmental factors, not because of ball moss.


Ball moss on trees

People notice ball moss more than trees do. The first few leaf layers of the tree at the top foot or two of the canopy are where the primary growth of the tree actually begins. A tree tends to grow most of its foliage at the ends of the limbs leaving the inside of the canopy bare. More than 90 percent of the sugars are produced in the top layers of the tree.

Meanwhile, ball moss is most often found on the interior branches of older trees. The interior branches have died from the lack of sunlight, not because of the ball moss. In fact, ball moss grows well in low light, low movement of air and high relative humidity, conditions that are found under the canopy of many shade trees. Mild winters help newly sprouted ball moss to become established, and then the range of ball moss increases.


Does it kill trees?

It has often been said that ball moss kills trees. In many cases, trees with ball moss are already in a stage of decline, but this is not due to ball moss. Usually this tree decline is caused by other environmental factors such as drought, excessive wet periods, disease or insects. While ball moss does not kill trees, it can become dense enough to restrict normal bud development when found growing on the twigs of trees where buds are present. There are also theories (not proven yet) that the "holdfasts" or roots of ball moss may damage branches.


When you look at a tree with ball moss covering its branches, it can look quite ugly - not something you want your landscape to have. Look at individual ball moss and you will see what resembles an air plant. There is beauty in nature, and each person sees it differently. Would you be as concerned if it would be covered with tiny flower petals?


Controlling ball moss

It is a personal choice. If you think that ball moss adds character to the trees in your landscape, just leave it alone.


If you think it is ugly and makes the landscape unattractive, there are several ways to control it. You can manually pick it off the branches. Time consuming and costly, you bet. You will not be able to get it all, but it will help for several years.


It can be mechanically removed with a high-pressure water spray. Hot water should not be used because it can damage the tree. You can prune out the branches that have the most moss on them.


Foliar Treatments

If you choose to use a foliar treatment, use a copper-based fungicide such as Kocide. A good time to apply this product is in the spring (March and April) when the moss is growing. A rain following treatment is ideal to help the copper be absorbed into the moss. Some even recommend spraying the tree with water following application if it does not rain. You must be careful with drift when using this product as it can harm ornamentals and fruit trees, particularly peaches and plums. It can also temporarily stain metal surfaces blue.


Baking soda is reported to be used to control ball moss by some, but we cannot recommend it because it is not labeled by the EPA.


Once the chemical has been applied and the moss is killed, it will become dark gray in color and the "leaf like" structures will point downward rather than be in an upright position. A second application in 12 months may be necessary. In most cases, it will take 18 months for these hold fasts to decay enough so that the ball moss will be dropped from the tree.


After treating your trees, use proper tree health management practices such as putting down a slow-release fertilizer and watering it well when needed.


You can see now that funny stuff is really not all that bad. In fact, you might try using it creatively from your trees in decorative natural settings. And it won't cost you a thing but your time and effort.


The Gardeners' Dirt is written by members of the Victoria County Master Gardener Association, an educational outreach of Texas Cooperative Extension-Victoria County. Mail your questions in care of the Advocate, P.O. Box 1518, Victoria, Texas 77901; or, or comment on this column at