I wish I could tell you the number of times clients will ask me about what is growing on their trees. Obviously, the concern is that the organism is causing damage to the tree.
This may be true on some things, but also may be a symptom to other tree problems. I will share information from a UGA publication prepared by Mila Pearce, IPM Homeowner Specialists.
First, to get an image of some of the items I am going to describe, you may want to get a copy of this educational publication or do a computer image search to get a visual impression.
The first item I want to discuss is lichens. I have probably received thousands of calls over the years on lichens.
You not only will find lichens on trees, but you can find them on rocks, window panes and plants. Lichens are blamed for causing poor tree health, but they are a symptom of other issues and are not the cause.
To be technical according to Pearce, lichens are composite, symbiotic organisms made up from members of different biological kingdoms. The lichen fungi will group up with items such as algae, cyanobacterium or even both to make food through photosynthesis.
Why is it on my tree? When living things, such as trees or plants, are stressed and are in decline, their canopy can be reduced. When the canopy is reduced, more sunlight can get into the interior and aid photosynthesis for lichens. How do you get rid of lichens?
Remember, that lichens are harmless to the tree, but is a sign that the tree is stressed. If you can improve the health of the tree, the tree canopy should become fuller.
This will cut down the available sunlight so photosynthesis will be reduced for the lichens to prosper. For more detail, read up on how the lichen fungi and its partners work together to make food. Pretty interesting.
Mistletoe is an evergreen parasitic plant found on many trees in our area. Since it is an evergreen, you can see it fairly easily right now. Mistletoe is known to have a wide range of host trees such as oak, maple, cottonwood and birch.
It is true that mistletoe can get minerals and water from the host, but it is capable of making food. Mistletoe leaves have chlorophyll and can make food like other plants.
Mistletoe will grow berries that can be eaten by birds. The birds will then spread the seed to other tree hosts by excreting the seeds. The seeds will germinate and grow into the tree. This is how it can obtain water and other mineral nutrients.
Mistletoe normally grows slow at first and takes years before producing seed. Most healthy trees can handle a small mistletoe infestation, but over time the individual branches can be damaged according to Pearce.
The branches will be more damaged by wind or cold. A heavy mistletoe infestation can affect overall tree health and even kill a tree if the tree is going through other stresses.
Removing mistletoe when it can be done easily can help. Pearce states that mistletoe may be pruned out one foot below the point of attachment.
If the mistletoe is located on a main limb or trunk, removing the top of the mistletoe and wrapping the cut with an opaque plastic will prevent sunlight and be helpful.
Finally, slime molds are a group of organisms that have over 700 different species.
You will find them in lawns, flower beds, gardens and anywhere organic matter is present. I get calls on folks seeing the blobs of slime mold in areas such as mulch.
I mention slime molds since you see it more after times of good moisture like we have now. Slime molds are more nuisance than harmful.
In mulch, raking the mold or jet spraying with water usually solves the problem.
For more information, contact Gordon County Extension at 706-629-8685 or email email@example.com.