by Larry Williams | Dec 9, 2014
From about mid November or December to March, deciduous trees have little to no foliage making us more aware of their shapes, forms and barks.
Here are a few trees to consider for adding winter appeal to your landscape.
Gary Knox, UF/IFAS Horticulturist, describes the crapemyrtle’s winter interest perfectly in his publication, “Crapemyrtle in Florida.” Knox writes, “When the leaves fall in winter, the crape myrtle becomes a living sculpture. The trunk and branches of tree-form plants have an attractively gnarled, sinuous character with smooth bark. Strips of bark peel off (exfoliate) in early summer to reveal mottled new bark ranging in color from pale cream to dark cinnamon to rich brown to bright orange.”
Here are some recommendations for crapemyrtles with attractive bark. ‘Acoma’ is an outstanding semi-dwarf hybrid reaching a mature height of 10 to 15 feet that has creamy beige bark and snow white flowers. ‘Apalachee’ is another outstanding selection with cinnamon orange bark and light lavender flowers. Its mature height is about 20 feet. The cultivar ‘Osage’ produces dark orange bark and medium pink flowers with a 20-foot mature height. ‘Fantasy’ is a large maturing variety growing to more than 20 feet tall with outstanding red orange bark and white flowers. More cultivars are listed in Knox’s publication available at http://edis.ifas.ufl.edu/MG266.
River birch is another tree with unusual papery peeling bark. The cultivar ‘Heritage’ is the closest to a paper white birch that will tolerate our hot summers. Expect a river birch to reach 40 to 50 feet in height and 25 to 35 feet in width.
Cultivars of Ulmus parvifo
Apalachee Crapemyrtle Bark Photo Credit: UF/IFAS
Drake Elm Bark Photo Credit: UF/IFAS
lia, Chinese elm, provide winter interest. “The showy, exfoliating bark reveals random mottled patterns of gray, green, orange and brown, adding great textural and visual interest, especially to its winter silhouette,” writes Ed Gilman, UF/IFAS Horticulturist, in his factsheet on Chinese Elm. This and other tree factsheets are available at http://hort.ifas.ufl.edu/woody. ‘Drake’ and ‘Allee’ are two popular Chinese elm cultivars. Chinese Elm can reach 80 feet in height but is more often seen at 40 to 50 feet with an equal spread.
American Hophornbeam, Ostrya virginiana, is an underused tree that grows to about 50 feet in height. Its grayish bark peels off in longitudinal strips revealing orange patches underneath.
Acer buergeranum or trident maple is a small, underused and hard to find tree. It usually is seen with multiple stems originating fairly low on the trunk giving the small tree a bushy appearance. It has noticeable orange-brown peeling bark.
by Eddie Powell | Oct 7, 2014
Fall color of Chinese tallow. Image credit UGA Extension
Chinese tallow tree (Sapium sebiferum (L.) a deciduous and very aggressive tree. Many people appreciate the fact that it grows fast, provides great shade, and has a beautiful reddish fall color.
Despite it’s attributes, it is highly invasive and considered a noxious weed. It has spread to every coastal state from North Carolina to Texas, and inland to Arkansas. In Florida it occurs as far south as Tampa. Chinese tallow was listed in Florida as a noxious weed in 1998 which means that possession with the intent to sell, transport, or plant is illegal in the State of Florida.
The Chinese tallow tree can reach heights of 30 feet and the seeds resemble popcorn, hence its other name, popcorn tree. These popcorn shaped seeds and the aggressive root system sprouts make it very hard to control the spread of this tree. Animals also spread the seeds freely!
Although the Chinese tallow has great fall color problems come with it.
Some questions to ask yourself:
- Do you want great fall color and a yard full of Chinese tallow?
- Hey what about the neighbor. Do they want Chinese tallow in their yard?
Think about more than fall when planting.
To read more on how to control Chinese tallow follow this link: edis.ifas.ufl.edu/FR251
by Eddie Powell | Sep 9, 2014
Throughout the year I get calls asking about this mossy-like stuff growing on the bark of trees. For the most part, the calls are in the spring time when people have come out of winter hibernation and see their landscape plants covered with this alien figure. I am here to say that it is not an alien figure, though it may look like it is. These are lichens.
Photo Credit: Eddie Powell
Lichens often get mistaken for some unusual fungus that is killing trees. However, lichens are not single organisms, but rather a combination of two organisms that live together in a mutually beneficial way. There are over 20,000 different types of lichens found in nature. Lichens consist of a fungus and an algae; the fungus is more dependent upon its algae partner which produces enough food for both to survive. Lichens are very different from plants in that they can survive a complete body water loss. During this time, brittle pieces that flake off can later grow into new lichens. When moisture becomes available again, the lichen absorbs water and returns to its fleshy form.
The lichens growing on trees and shrubs are not parasites and do not harm the plants in any way. The lichens use the landscapes as a structure to become established.
There are four different forms of lichens found, crustose (crust-like, growing tight against the substrate), squamulose (tightly clustered and slightly flattened pebble-like units), foliose (leaf like, with flat sheets of tissue not tightly bound), and fruticose (free-standing branching tubes). Colors range from white to gray, green, red, yellow, and black. Lichens commonly found in our area are in the crustose, foliose, or fruticose form, and are white, gray, or gray-green in color.
Because lichens produce chemicals, they have very few natural predators. However, the most serious threat to lichens is air pollution. Most lichens will not grow in a polluted atmosphere and therefore you should be glad to see lichen here or there in your yard, as this is an indication that the air is relatively clean.
by Mary Salinas | Jun 10, 2014
A mimosa tree invader in a natural area. Photo by Mary Derrick, UF IFAS.
All along the roadsides and in home landscapes this time of year, a profusion of fluffy pink blossoms are adorning trees known as Mimosa, or Albizia julibrissin. This native of China was introduced to home landscapes in this country in the 1700’s to enjoy the fragrant, showy flowers and fine, lacy foliage. However, there is a dark side to this lovely tree. After blooming, it produces an abundance of pods each containing 5 to 10 seeds. Seeds can be spread by wildlife and water; this is evidenced by the appearance of mimosa trees along the roadways, streams and in our natural areas. The seeds can also remain dormant for many years, allowing seedlings to keep sprouting up long after the mother tree is gone.
Mimosa has been categorized as an invasive exotic plant in Florida as it has not only naturalized, but is expanding on its own in Florida native plant communities. This expansion means that our native plants in natural areas get crowded out by the mimosa as it reproduces so prolifically.
Bloom and foliage of the invasive mimosa tree. Photo by Mary Derrick, UF IFAS.
[important]The Florida Exotic Pest Plant Council (FLEPPC) publishes a list of non-native plants that have been determined to be invasive. Click here for the most recent 2013 list![/important]
The first step in controlling this pest plant is to remove existing plants in the landscape. Cutting it down at soil level and immediately painting the stump with a 25% solution of glyphosate or triclopyr should do the trick. Other details and control methods can be found here.
There are some native trees that make excellent alternatives to Mimosa such as fringe tree (Chionanthus virginicus), silverbell (Halesia carolina) and flowering dogwood (Cornus florida).
For more information:
Albizia julibrissin: Mimosa
UF IFAS Center for Aquatic and Invasive Plants: Mimosa
by Larry Williams | Jun 3, 2014
Glistening webbing formed by tree cattle (psocids) Photo credit: Doug Caldwell, University of Florida
Many people are noticing small insects on trunks and branches of their trees. When disturbed, these insects move in a group and are commonly called tree cattle because of this herding habit. They are ¼ inch brownish-black insects with white markings.
Some people assume that these insects will injure their trees but they are harmless. They could be considered beneficial.
These insects are called psocids (pronounced so-cids). They have numerous common names including tree cattle and bark lice. They feed on lichen, moss, algae, fungi, spores, pollen and the remains of other insects found on the tree’s bark. As a result, they are sometimes referred to as bark cleaners.
Tree cattle may form webbing. This webbing is tight against the tree’s trunk and/or limbs. It appears suddenly. The webbing is used as a protection from weather and predators. Underneath you may find psocids.
The glistening webbing may attract a person’s attention resulting in the tree being visually inspected from top to bottom. A dead branch or other imperfections in the tree may be noticed and then wrongly blamed on the tree cattle. I’ve talked to homeowners that sprayed their trees with insecticides or that hired pest control businesses to treat the trees as a result of finding the webbing/psocids. One person told me that he cut down a tree after finding tree cattle. He wrongly assumed that these insects were pests that might move through the area and kill trees. He thought he was doing a good thing.
Adult female psocids lay eggs in clusters on leaves, branches and tree trunks. After hatching, the immature insects (nymphs) remain together under their silk webbing. Adults have wings which are held roof-like over their body. Nymphs are wingless. Psocids usually have several generations per year in Florida.
After seeing the webbing and/or insects, many people insist on spraying insecticides because they believe these insec
Under the webbing live hundreds of psocids. Photo credit: UF/IFAS Jim Castner
ts are damaging their trees. But as mentioned, they are bark cleaners and do not damage trees. If the silk webbing is considered unsightly, a heavy stream of water from a garden hose can be used to wash insects and webbing off infested trees. If nothing is done, the webbing usually goes away in several weeks.
Psocids can be found on many rough-barked hardwood trees and palms. Occasionally, they may be found on wood siding, fence posts or similar areas.
