by Gary Knox | Oct 28, 2014
Figure 1. Paraná pine has a narrow, pyramidal form when young.
Paraná Pine, Araucaria angustifolia:
An ancient-looking conifer for modern landscapes
Paraná pine is a primitive-looking conifer valued for its unusual horizontal branching, sharply pointed triangular needles and neat, symmetrical form. The primitive appearance of this evergreen tree results from its resemblance to and relationship with an ancient group of conifers that dominated forests more than 65 million years ago.
Not a true pine, this dark green tree has a narrow, pyramidal shape when young. Paraná pine is considered fast-growing, and a tree planted at Gardens of the Big Bend in Quincy, Florida, reached a height of 30 feet and a width of 14 feet in eight years (Fig. 1).
Paraná pine reaches a mature size of 60 to 115 feet after 50 to 90 years or more in forests of southern Brazil. As it approaches maturity, the lower branches gradually die and the tree develops a dramatic dome shaped crown that somewhat resembles a candelabra due to upward pointing branch tips. Paraná pine is considered a large, long-lived tree. Fully mature trees may be 140 to 250 years of age, have heights up to 160 feet, and trunk diameters exceeding three feet (Fig. 2).
This evergreen conifer has distinctive sharp-pointed, tough, scale-like needles (Fig. 3). The dark green needles are triangular shaped and about 1 to 2.5 inches long. Needles tend to be tufted at outer ends of stiff, horizontally held branches. Needles persist for up to 15 years and cover all plant parts except the trunk and major branches. The stiff, sharp needles make the tree and branches difficult to handle, while also acting as a deterrent to deer feeding and other animal predation as well as foot traffic.
Figure 2. Closeup of the rough bark of Paraná pine.
Paraná pine is usually dioecious, meaning male and female flowers are borne on separate plants. Pollen cones are oblong, up to seven inches long and about one inch wide at the time of pollen release. Wind carries pollen to female plants bearing seed cones. Young female trees begin to set seed between 12 and 15 years of age. After pollination, seed cones mature about 18 to 36 months later, usually in fall. Seed cones are brown, globe shaped, 7 to 10 inches in diameter, and are usually found in the upper canopy of trees. Each cone holds about 100 to 150 two inch nut-like, narrowly winged seeds (Fig. 4). Cones fall when mature and break apart, dispersing seeds that germinate soon thereafter. Seeds are eaten by mammals and birds, thus also dispersing seeds.
This tree once covered vast areas of subtropical forests in southern Brazil and neighboring portions of Argentina and Paraguay. Native Americans gathered cones to harvest the seeds for food. European settlers recognized Paraná pine as an important timber tree and it was logged extensively through the 20th century. Paraná pine now is one of the rarest trees in Brazil and is considered critically endangered due to a declining population caused by habitat loss and exploitation. In recognition of the past importance of Paraná pine, this tree is the symbol for the Brazilian State of Paraná.
The seeds, locally called pinhões, are still a prized food in Brazil. The seeds are similar to large pine nuts and are eaten after roasting or cooking in salt water.
Figure 3. The triangular shaped needles of Paraná pine are stiff and extremely sharp.
Other common English names for Paraná pine are Brazilian pine and candelabra tree. Common Portuguese names for Araucaria angustifolia are pinheiro-do-Paraná, pinheiro, araucária, pinho, pinho Brasileiro, pinheiro Brasileiro, pinheiro são josé, pinheiro macaco, pinheiro caiová, pinheiro das missões, curi, and curiúva. Common Spanish names are pino blanco and pino de Missiones.
Despite the common names, Paraná pine is not a pine (Pinus spp.) and instead is related to the Monkey-puzzle tree (Araucaria araucana;), Bunya-bunya tree (Araucaria bidwillii;), and the Norfolk Island pine (Araucaria heterophylla;), commonly encountered in southern Florida.
Paraná pine is sometimes confused with China fir (Cunninghamia lanceolata;), another large conifer commonly encountered in old landscapes along the Gulf Coast and north Florida. China fir differs in having pointed needles, bright green coloring, and a broader, irregular pyramidal form.
Paraná pine prefers well drained, slightly acidic soil in sun or light shade. It grows best in a mild, warm temperate climate typical of USDA Cold Hardiness Zones 7-9, and can tolerate occasional severe freezes. Paraná pine transplants well: a tree at Gardens of the Big Bend (Quincy, FL) was moved by tree-spade after four years. Subsequent growth continued at the same rate as before moving. Pests and diseases have not been reported.
Seeds must be obtained fresh and are viable for only about six weeks. Typically, freshly harvested seeds are ordered from Brazil and planted soon after being received. Seeds germinate easily within three months of sowing (Fig. 5).
Figure 4. Seeds of Paraná pine are about two inches long.
As a “living fossil”, Paraná pine is prized for its unusual appearance, horizontal branching and dark green color. This evergreen conifer grows too large for most residential situations. Paraná pine is best used as an accent or conversation piece in arboreta, botanic gardens, parks, campuses, golf courses and other large-scale landscapes.
Figure 5. Although perishable, fresh seeds will germinate within three months of sowing.
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 Sheila Dunning | Aug 19, 2014
Pine bark beetles are frequent pests of stressed pines in the southern United States. The five most common southern pine bark beetle species include three in the genus Ips. Ips beetles usually colonize only those trees that are already stressed, declining, or fallen due to environmental factors. Infestations may occur in response to drought, root injury, disease, lightning strikes or other stresses including flooding.
Ips calligraphus usually attacks the lower portions of stumps, trunks and large limbs greater than 4” in diameter. Early signs of attack include the accumulation of reddish-brown boring dust on the bark, nearby cobwebs or understory foliage. Ips calligraphus can complete their life cycles within 25 days during the summer and can produce eight generations per year in Florida. Newly-emerged adults can fly as far as four miles in their first dispersal to find a new host tree, whichever one is the most stressed.
Most trees are not well adapted to saturated soil conditions. With record rainfall this past April, the ground became inundated with water. When the root environment is dramatically changed by excess moisture, especially during the growing season, a tree’s entire physiology is altered, which may result in the death of the tree.
Water saturated soil reduces the supply of oxygen to tree roots, raises the pH of the soil, and changes the rate of decomposition of organic material; all of which weakens the tree, making it more susceptible to indirect damage from insects and diseases.When the ground becomes completely saturated, a tree’s metabolic processes begin to change very quickly. Photosynthesis is shut down within five hours; the tree is in starvation mode, living on stored starches and unable to make more food. Water moves into and occupies all available pore spaces that once held oxygen. Any remaining oxygen is utilized within three hours. The lack of oxygen prevents the normal decomposition of organic matter which leads to the production and accumulation of toxic gases such as carbon dioxide, methane, hydrogen sulfide and nitrogen oxide. Additionally, within seven days there is a noticeable root growth loss. Roots only develop when soil oxygen levels are at 5% -15%. Over time, the decaying roots are attacked by pathogens. The loss of root mass from decay and fungal attack leaves the tree prone to drought damage. After only two weeks of saturated soil conditions the root crown area can have so many problems that decline and even death are imminent.
When a tree experiences these anaerobic soil conditions it will exhibit symptoms of leaf loss with minimal to no new leaf formation. This usually appears two to eight weeks after the soil dries out again. Many trees will not survive, especially the more juvenile and mature trees. However, well established trees may still decline several years later, if they experience additional stresses such as drought or root disturbance from construction.
There is little that can be done to combat the damage caused by soil saturation. However, it is important to enable the tree to conserve its food supply by resisting pruning and to avoid fertilizing until the following growth season. Removal of mulch will aid in the availability of soil oxygen. Basically, it is a “wait and see” process. While water is essential to the survival of trees, it can also be a detriment when it is excessive, especially for drought tolerant pine species such as Sand Pine, which is prevalent throughout the coastal areas.
For urban and residential landscape trees, preventative strategies to avoid tree stress and therefore reduce the chances of infestation include the following:
1) avoiding compaction of, physical damage to, or pavement over the root zones of pines,
2) providing adequate spacing (15-20ft) between trees,
3) minimizing competing vegetation beneath pines,
4) maintaining proper soil nutrient and pH status and
5) limiting irrigation to established pine areas.
When infested trees are removed, care should be taken to avoid injury to surrounding pines, which could attract the more harmful pine bark beetle species Dendroctonus frontalis, the Southern Pine Bark beetle.
There is no effective way to save an individual tree once it has been successfully colonized by Ips beetles. In some cases, the application of an approved insecticide that coats the entire tree trunk may be warranted to protect high-value landscape trees prior to infestation. UF/IFAS Extension can assist with recommendations.
by Mary Salinas | Jul 15, 2014
We all seem to have this dilemma: A desire to re-landscape or just add a few plants to an area, but not knowing what would be the best choice. Plants need to be compatible with their location. The right plant should be chosen for the right place. Many have particular light, moisture and zone requirements in order to do their best. The ultimate size of the plant is also an important consideration; if you want to avoid constant pruning, choose plants that only grow to size you would like to ultimately have. Some great resources are provided below to get you the information you need.
UF IFAS Extension has a brand new app for your mobile device or web! The app contains a database of over 400 Florida-friendly plants is searchable by plant name, type, shape, native status, light requirements and more. The yearly subscription is only $1.99 to have great info on the go.
The downloadable 104-page Florida-friendly Landscaping Guide to Landscape Design and Plant Selection not only has photos and detailed information about plants by category, it also has great ideas on how to improve your landscape design! 
UF’s Florida Yards & Neighborhoods maintains a searchable Florida-friendly Plant Database. Make choices based on region, plant type, light and moisture quantity, soil texture salt tolerance.
For native plants, the Florida Association of Native Nurseries has two websites where you can find plants for your particular zone, plant community (like at the beach or in pine flatwoods), plant type and by wildlife usage. There is a site designed for nursery professionals that lets you find local wholesale growers and also a similar site for homeowners that has resources on where to find desired plants at local nurseries.
Speaking of native plants, the Florida Native Plant Society also has a searchable list of plants appropriate for your particular needs.
Gardening Solutions has lots of great information for lawn, landscape and garden by category, and it is easily accessed.
Happy Gardening!
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
