Indian River County Extension Service
1028 20th Pl, Suite D
Vero Beach, FL 32960
February 6, 2002
FOR RELEASE: February 10, 2002
Daniel F. Culbert, County Extension Director
WHATíS THAT IN MY TREE?
The height of the tourist season in the Indian River area coincides with the time of year when the foliage on our trees is the thinnest. Itís also a busy time here at the Extension office with many requests for information about all that stuff growing in our trees. People we talk to are concerned that all these unusual things are killing their trees, and want to know how they should be removed.
Only few of these plants are harmful. Most are "just there", and a few of them are actually rare plants that deserve recognition. Information for todayís column comes from University of Floridaís Extension Specialists and from the University of South Floridaís Institute of Systemic Botany.
Mistletoe is a Parasite
Mistletoe grows in Laurel Oaks, Hickories and a few other hardwood trees. It is very apparent in the thin foliage of our semi-deciduous trees at this time of year. It appears as a darker green ball of foliage on an otherwise bare tree canopy. Of all the items found growing on our trees, this is one of the few which can harm our urban forest.
Common or Christmas mistletoe (Phoradendron serotinum) is the species found growing in local deciduous trees. Birds eat and disperse the mature white sticky fruits. They are deposited in the cracks of the bark, and grow into the wood. Mistletoe is semiparasitic: it has green leaves that provide some energy, but it also is absorbing the sap from its host tree.
In a healthy tree, mistletoe may not be much of a concern. But, if the tree is stressed from construction damage, disease or old age, this parasite will take its toll. Mistletoe can be cut out of the tree canopy, but the branch that hosts this parasite should be cut back to several inches below the connection point to insure that it does not grow back. This kind of trimming may not be possible on larger limbs of the tree. Scientists are looking at the use of a plant growth regulator chemical, ethephon, as a selective mistletoe management spray. Itís use on local trees has not been approved as a pesticide by the EPA.
Spanish Moss and Ball Moss
With thin foliage on our trees, many "air plants" are apparent at this time of year. Spanish Moss and Ball Moss are bromeliads, native plants closely related to the pineapple and other epiphytes. Besides this seasonal view of the air plants growing in our oaks, we may find more epiphytes on those trees that are weakened by root damage. Trees under stress from over watering, poor planting, construction damage or old age may also have thinner foliage, allowing more light to penetrate into the branches. Light stimulates the growth of moss and bromeliads. So, air plants grow faster on stressed trees because the tree is weakened, but these visitors are not the cause of poor tree growth.
Although a tree might be weakened, it would not likely be killed by Spanish or Ball moss. Occasionally, air plants can become so thick that it shades the leaves of its host. When a diseased or poorly attached limb with lots of these air plants are heavy with rainwater, the branch could break.
Spanish Moss (Tillandsia usneoides) is a symbol of the South, found hanging from tree limbs, especially live oak and cypress. It is gray when dry and light green when wet, and it hangs from tree branches in garlands as long as 20' or more. The flowers are inconspicuous, pale green or blue, and fragrant at night. The stems and leaves are slender and curly, and covered with tiny silvery-gray scales that catch water and nutrients (in dust particles) from the air. Spanish moss has no roots, so it is not a parasite. That is, it does not take nutrients or water from the host tree on which it lives.
Until the 1960's, Spanish moss was harvested commercially,
and tons of it used for mattress and furniture stuffing. If used for this
purpose, be aware that tiny pests (especially red bugs or chiggers) that may be
lurking within, and the material can be treated by microwaving or boiling. In
spring and summer, Spanish moss on live oak or cypress limbs may provide nesting
places for birds, and there is one species of spider that occurs nowhere but in
Ball Moss (Tillandsia recurvata) is a gray-green epiphyte found on tree branches and can sometimes grow on telephone wires. It grows to a clump 6-10" in diameter with scaly, recurved, linear leaves 2-6" long and is often mistaken for a small clump of Spanish Moss. It grows on most kinds of trees but seems to be especially fond of live oak In nature, the tiny seeds are blown by the wind until they land on a tree branch where they stick fast and develop root-like attachments to the outside of the bark.
Ball Moss is a nitrogen fixer. That is, it is able to convert atmospheric nitrogen (which is unusable to plants) into a form that plants can use. With the exception of 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.
According to Dr. SeRichard Wunderland of the University of South Florida, there are seven other native bromeliads that can be found in our county. The Giant Airplant or Giant Wild Pine (Tillandsia utriculata) is an endangered plant that looks like the top of a pineapple that is stuck on a tree branch. Bartram's Airplant (Tillandsia bartramii) is another local native that is somewhat smaller in size than the Giant Airplant, and the Southern Needleleaf (Tillandsia setacea) looks a lot like a bunch of reddish pine needles. A threatened species found locally is the Inflated & Reflexed Wild Pine (Tillandsia balbisiana). Three other related species lacking common names can be found in Indian River County.
Note that some of these species are at risk. Much of this is due to habitat destruction and over collection. And now there is another threat, an introduced insect that chews holes in the base of these epiphytes. It is known as the Evil Weevil and was accidently introduced into Florida in 1989. The use of natural predators to this insect is under development, and the use of chemical insecticides for immediate management would be unacceptable. An effort is being spearheaded by native plant enthusiasts to collect the seed from these species and keep small populations of these plants protected from the insect. See the "Save Floridaís Native Bromeliads" website for more information. (http://savebromeliads.ifas.ufl.edu/ ).
Have you noticed that in our county the barrier island is called "Orchid Island?" The name does not come from the Town of Orchid, rather, the island and the town have developed their moniker from the presence of native orchids that were found growing here. Some orchids take up space on tree branches where conditions are ideal for their growth, but do not have any direct vascular connections to the trees on which they live.
The most well know of orchids found growing naturally in Indian River environment is the Florida Butterfly Orchid (Encyclia tampensis), which grows as a clump of bulbous "grass" on oaks. The flowers look like small butterflies, about one inch in size. Most of the petals are yellowish, with the bottom part of the flower a white and pink color. This orchid and all native plants should not be taken from the wild without permission.
Ferns, Lichens & Conks
Several species of ferns can also take up residence on tree branches. The Resurrection Fern (Polypodium polypodioides) is an epiphyte that can take up resident on Live oaks and sometimes on rocks or dry ground. They creep along the furrows of the bark, and produce 6 inch long fronds. These leaves gray and curled up when dry, but green when wet and unfurled. Resurrection fern is not a parasite. It gets its water and nutrients from rain and dust, and causes no harm to the tree that supports it. This little plant is the "miracle plant" sold as a novelty item.
Another visitor to the bark of our trees are numerous kinds of lichens. These plants come in many different forms, and are actually an organism that is composed of a fungi and an algae. The algae give the color and provide the food for the lichen, while the fungi gives the protective from for these unusual plants. Again, these gray, green, red or yellowish patches take up space on tree limbs and branches, but do not harm the tree in any way. Some find their appearance unappealing, and landscape perfectionists might find someone willing to spray a fungicide on their tree to discourage them. The University of Florida does not have any fungicide recommendations for this purpose.
At the base of some trees, half mushrooms can sometimes be see growing from the trucks or roots of distressed trees. These structures are the fruiting bodies of fungi that can be either natural decomposers, or they can actually be attacking a declining tree. A group of fungi know as Gandoderma are becoming well know as a terminal death sentence for many of our palms; there are other species of Gandoderma that can infect hardwood trees, but the same species do not effect palms. The presence of any kind of mushroom at the base of a tree is not a good sign, and experts should be called if the tree is to be retained in our Florida Yard.
If you need additional information on whatís growing in your trees, visit our Master Gardeners, or call or stop by our office. For those with other questions about Florida Yards, our office holds Master Gardener Clinic hours at the Extension office (1028 20th Place, Suite D, Vero Beach) every weekday morning and most afternoons, Wednesday morning at the Sebastian City Hall and the first Saturday of the month at the Environmental Learning Center. Our phone number is 770-5030, and our email address is Indian@mail.ifas.ufl.edu .