by Evan Anderson | Feb 27, 2020
This time of year, owners of woody plants might notice that leaf canopies are thin. Fruit and ornamental trees, shrubs, and bushes might have shed some leaves over the winter or thinned out due to disease, cold damage, or other problems. When this happens, it can call more attention to the stems of these plants, which may sport a fuzzy, frilly growth on them. More than once I’ve heard people ask, “What is this growing on my plant and how do I stop it from killing it?”.

Red Tipped Lichen – Image Credit Evan Anderson UF / IFAS Extension
Lichen is the fuzzy growth in question, and the good news is that it doesn’t harm the plant it grows on. Lichen is an organism that’s a combination of fungus and either algae or cyanobacteria. The algae photosynthesizes and produces energy to share with the fungus, which provides protection and support. Thankfully, they’re pretty self-contained, and don’t need to steal nutrients or water from whatever they’re growing on. That means they can grow just about anywhere – on rocks, fence posts, tree bark, or on the ground (if you’ve seen deer moss growing in the woods, that’s a lichen!). Again, they are NOT parasitic and do NOT hurt plants.

Lichen on Tree Trunk. Image Credit Evan Anderson, UF / IFAS Extension
It’s common to find lichens growing in many different forms and colors. One alarmed tree-owner brought me a branch decorated with a round blotch that had a bright reddish edge. A Christmas Wreath lichen had found a home on her tree, and while the red rings it forms may look alarming, they’re just as innocuous as other lichens. There may be multiple forms of lichen growing in close proximity on a branch, as well. Flat, wavy, rippled, filamentous, bushy, and powdery looking lichen might all mix together to make a strange (or beautiful) looking collection on a tree.
by Evan Anderson | Jan 27, 2020
North Florida weather brings its ups and downs, and there are times during the winter season when the downs are low enough to trouble even cold-tolerant crops. Gardeners who wish to keep their plants growing as long as possible, or give them a head start in the spring, may want to consider installing low tunnels.
The term ‘low tunnel’ refers to a structure used for season extension that is usually made of hoops covered with some material, such as fabric or plastic. A low tunnel, as you might surmise, is low to the ground, like a miniature greenhouse that just covers the plants. They are usually no more than a few feet in height. A high tunnel, by comparison, is tall enough to walk in, but with a similar sort of construction.
These are versatile structures, which can act as more than just protection from cold. Low tunnels can be easily modified to provide extra shade for crops during the hottest months. A lighter fabric or fine mesh can also be used as protection from insect pests. Low tunnels can be constructed to stand on their own or may be integrated into a raised bed. They may even be placed inside a larger structure such as a high tunnel to offer a double layer of protection.

An example of a low tunnel using wire hoops and plastic mulch to prevent weeds. Photo credit – B M. Santos, UF / IFAS Extension

Pipe Bender for bending hoops for low tunnel systems. Image Credit Evan Anderson, UF / IFAS Extension
The cover of a low tunnel can be plastic, fabric, shade cloth, or even insect netting, depending on the needs of the crop. The hoops that hold the cover may be made of any sturdy material, such as wire, pieces of PVC, or metal electrical conduit. Hoop benders are available to help bend metal conduit to the correct shape. For more information about low tunnels, please see this EDIS publication.