DON'T LET THE NAME FOOL YOU
Ball moss is not a moss at all and it
won't harm trees
April 12, 2007
BY BARBARA THEDIN - VICTORIA COUNTY MASTER GARDENER
EDITED BY CHARLA BORCHERS
While driving through the countryside in the
PHOTOS BY BARBARA THEDIN/VICTORIA COUNTY MASTER
GARDENER 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. |
NOT A MOSS AT ALL
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
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