Spanish moss isn't a moss, or a parasite


Published: Wednesday, January 16, 2008 at 6:01 a.m.
Last Modified: Wednesday, January 16, 2008 at 12:00 a.m.

There's something about live oaks draped in Spanish moss that defines The South.

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Clumps of ball moss become more apparent when leaves drop from the trees. It is not parasitic; neither is Spanish moss.

MARINA BLOMBERG/The Gainesville Sun

But Spanish moss (Tillandsia usneoides) is not just here; it has the largest distribution of any species in the Bromeliaceae family. Its range is as far north as Virginia, westward to coastal Texas and as far south as the southern Andes (Chile, northern Argentina and Bolivia) including the West Indies in between. It has been introduced to other temperate and tropical climes, such as Hawaii, where it is being monitored so it doesn't get out of hand.

It is sensitive to pollution and does not thrive in areas with stagnant, dirty air (which means the atmosphere around The Sun on SW 13th Street must be pristine).

Spanish moss is not a parasite; its tiny gray scales trap nutrients and moisture from the air. There are no roots. Therefore there is a higher incidence of moss around lakes and rivers, where the humidity is high.

While it is called a moss, it is not; it is a member of the division Magnoliophyta, the flowering plants. The inconspicuous flowers are fragrant and appear around March/April. When the seed pods open the following winter, the seeds use hairy sails to drift to other trees or suitable sites to lodge in ridges in the bark. Once established, the temporary root - actually, just a hold-fast - becomes unnecessary.

Some trees - camphor for one - exude an allelopathic substance and resist infestations. Crape myrtles seem to have an uncanny attraction for the moss, and this may be because they are deciduous and allow more light into their framework.

A heavily infested tree, however, can suffer from secondary problems. The amount of moss can shade the leaves, weakening the tree. Long festoons of moss, when wet from rain or irrigation, can weight down branches which may break.

Pest control companies can spray trees with a product that will start eliminating the moss. Most contain copper sulphate. Daniel Dye, training coordinator for Florida Pest Control, said his company gets a lot of business in the winter from people wanting to thin out - or completely eliminate - the overgrowth of moss on their trees. He had it done at his own home near Brooker, using a tanker truck to reach nearly 80 feet to spray the copper solution to the top of an old live oak whose limbs were bearing heavy congregations of Spanish moss. "That stuff gets real heavy when it is completely wet."

He said it takes 8 to 12 weeks for the moss to begin dehydrating and a year to 18 months for it to fall naturally - or blow off - the limbs.

He noted a lot of pecan grove owners request the service because heavy moss coverage decreases production of the nut trees.

It can take over a year for the moss to succumb to the spray, and then it will need to be pulled off the tree. Hickerson said the spray kills the seeds, while simply pulling away live moss disperses the seeds and often leaves traces of moss branches to rekindle the growth.

Spanish moss serves as a home to a variety of animals. The most notorious are chiggers but a spokesman for a pest control company said chiggers are only found on moss that is near or on the ground, not farther up into the tree. The most creative are the Baltimore oriole and warblers, which will build a nest right inside the hanging festoon. Other birds use the strands in building their nests, and bats will sometimes hide inside a large clump.

Spanish moss was a large commercial commodity in the early 1900s, when it was collected, dried and used as stuffing for car seats. When the living portion drops away what is left is a black, wiry product. Native Americans used this wiry substance for a variety of purposes, including weaving into horse blankets and creating fire arrows.

Modern uses of moss are mulches and crafts. Be sure to eliminate critters in the moss. While microwaving is suggested by several sources, the best way is to soak the moss in a dish detergent/water solution and then air-dry.

Ball moss (Tillandsia recurvata) is a gray-green epiphyte found on tree branches or telephone wires. It is often mistaken for a small clump of Spanish moss. It grows in clumps 6 to 10 inches in diameter on most kinds of trees, but seems to be especially fond of live oak. I find it on crape myrtles. It also sometimes ends up on utility wires.

As with Spanish moss, tiny seeds are blown by the wind until they land on a tree branch or bark. They stick fast and develop root-like attachments to the outside of the bark. They are also not parasitic, but if you don't like the way they look, just carefully pull them off.

Ball moss makes an interesting - if not drab - epiphyte tied to a piece of bark and hung on a wall. Let it live outdoors in the summer, protecting from freezing temperatures in the winter (even though mine on my crape myrtle look healthy after last week's hard freeze).

Interestingly, ball moss is able to convert nitrogen in air (which is unusable to plants) into a form that plants can use. Except for the beans and peas, most plants cannot do this. So when ball moss falls to the ground and decomposes, it provides fertilizers for other plants.

Marina Blomberg can be reached at 374-5025 or blombem@gvillesun.com.

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