There are some key practices that are necessary to make sure your trees and shrubs establish and thrive in your landscape. Learn a few pointers from UF IFAS Extension Escambia County to promote healthy establishment after correct plant installation. Learn about installing shrubs with the UF IFAS publication Establishing Shrubs in the Florida Landscape.
Tree dieback is a complex syndrome and slow developing. Dieback is essentially a process in which trees lose leaves and limbs. This usually occurs as a result of severe stress to the tree’s bark or root system, but could be a result of a declining life cycle.
It’s important to note that there is a significant balance between a tree’s root system and the number of leaves and limbs it can support. For example, if a tree loses part of its root system, possibly due to disease or lawn equipment damage, the tree will forfeit a portion of its leaves. Dieback doesn’t happen overnight, though. It’s a slow process, with larger trees taking much longer time for signs of stress to emerge. However, a large tree root system is very sensitive to damage, whereas a small tree will adapt quickly and is much more resilient to damage. So, what can be done to prevent dieback in trees?
First and foremost, trees, like all living things, have a natural life cycle. Regardless of how you care for your trees, dieback will occur. The most important management measure in extending the life of a tree is to protect the root system and bark.
With each passing year, a tree grows new bark in the rejuvenation process. The bark replacement process inevitably becomes more difficult as the tree gets older and in turn the tree is more and more susceptible to dieback. If the bark becomes damaged, especially later in the tree’s life cycle, then fungi and insects have a much greater chance to cause serious harm. Treating bark damage with a wound dressing to prevent decay is the recommended procedure.
Lichens come in many forms and are commonly blamed for the decline and death of trees and shrubs, however they do not cause harm. Credit. Sydney Park Brown and Joseph Sewards, UF/IFAS.
A common misconception is that epiphytes, such as lichens and Spanish moss, are tree diseases. Epiphytes are known as “air plants” and thrive in the Panhandle. They survive on moisture and nutrients in the atmosphere and are harmless to trees. However, a tree that becomes inundated with epiphytes may be an indicator of excessive soil moisture, which may lead to root rot.
Lawn weed killers can have detrimental effects to trees, even if the application seems to be from a safe distance. When using a weed killer near a tree’s root system, confirm on the label that the product is designed to kill green growth only. It can’t be overstated that excessively fertilizing an old tree will greatly accelerate the decline of the tree. Some may think this will stimulate a tree and extend its life, but instead it will do the opposite. Young trees can tolerate fertilizer applications, as they need crown growth. Older trees will simply become top heavy, and structural damage will likely occur.
Don’t forget, trees need space too. A mature tree forced to occupy a small space will simply not adapt. Be sure to have adequate spacing when planting younger trees and shrubs in the vicinity of older trees. Also, keep your trees pruned away from touching structures and utilities.
Tree dieback is a complex issue to manage. By following these measures, you can help extend the life of your trees and continue to have a picturesque landscape.
For more information on tree dieback, contact your local county extension office.
Please visit Florida Friendly Landscaping, http://fyn.ifas.ufl.edu/, for more information on maintaining your landscape.
For more general information on lichens, please see UF/IFAS EDIS document “Spanish Moss, Ball Moss and Lichens-Harmless Epiphytes” by Joe Sewards and Dr. Sydney Park Brown: https://edis.ifas.ufl.edu/pdffiles/EP/EP48500.pdf
UF/IFAS Extension is an Equal Opportunity Institution.
A spotted Japanese Persimmon leaf, Image Credit: Matthew Orwat
In gardening, brown or black spotted leaves are most often an indicator of disease problems or growth issues. This causes us to worry and seek answers as to why this is occurring. This is good since the first step in solving a plant growth or disease issue is diagnosis.
During Fall, the presence of brown or black spots on leaves of shade and fruit trees is usually not cause for alarm, as it might be in the spring or summer. Certain shade trees such as Southern Magnolia, Japanese Magnolia, various maple, persimmon and oak in the Red Oak group show substantial brown and black leaf spotting as Fall arrives. This is due to the fact that these leaves have been attacked by fungal pathogens and insects since Spring and resistance to damage has broken down over time. As Fall progresses, these leaves will senesce (purposeful deterioration due to age, such as at end of season) and fall to the ground. Therefore, this ugly spotting is part of natural seasonal leaf decomposition in deciduous trees.
Although Fall leaf spotting may not be something to worry about, oftentimes we run into plant problems that need quick diagnosis. Fortunately, your local Extension Office and the Plant Disease Diagnostic Clinic at NFREC exists for these situations. If you need help with plant problems, feel free to contact your local Extension Agent or Master Gardener Volunteer group and they will figure it out or send it along to the Diagnostic Clinic (small diagnostic fee if using NFREC clinic services).
If you happen to live in or near Washington County, we are launching our Second Mondays Free Plant Clinic. Staffed by knowledgeable and friendly UF / IFAS Master Gardener volunteers and your County Extension Agent, we will be available every second Monday of the month from 10am to 2pm at the Washington County Ag Center, which houses the UF / IFAS Extension Office. We will be located in the Master Gardener Volunteer Library which is just left of the central auditorium double doors. The launch date of this plant clinic is Monday, October 11th. See you then!
As homeowners, we do value our trees and no one wants to lose a shade tree especially on the house’s south side in Florida. On a recent site visit, a hickory tree had multiple concerns. Upon closer inspection, the tree had a bacterial infection about 30” off the ground with a smelly, black-brown ooze seeping forth. The leaf canopy was riddled with beetle holes and leaf margins were chewed by caterpillars. When leaves were viewed under the microscope, thrips (insects) and spider mites were found running around. The biggest homeowner cosmetic concern arose from hickory anthracnose (fungus) and upon closer inspection found the leaves to have hickory midge fly galls. The obvious question is should the tree come down? I’ll have you read the whole article before giving you the answer.
Each hickory gall is approximately 3/16″ wide.
Hickory anthracnose or leaf spot as seen in the banner photo is caused by a fungal infection during the wet summer months in Florida. The homeowner can usually recognize the disease by the large reddish brown spots on the upper leaf surface (sending a sample to the NFREC Plant Pathology Lab will confirm the diagnosis) and brownish spots with no formal shape on the bottom. Be sure to rake and remove all leaves to prevent your disease from overwintering close to the tree thus reducing infection next year.
A hickory gall has been cut in half to show the leaf tissue.
The fungus can be lessened by good cultural practices and appropriate fungicidal applications. Please remember it is best left to professionals when spraying a large tree. This alone is not cause to remove your tree.
Hickory gall is caused by the hickory midge fly, an insect that lays eggs in the leaf tissue. The plant responds by building up tissue around each egg almost like the oyster when forming a pearl.
As the gall tissue grows, eggs hatch and larva start to feed on this tissue. The larva will continue to
The larva has eaten all soft material inside the gall and is ready to pupate.
feed until it is ready to pupate within the gall. After forming a pupa, the midge fly will eventually emerge as an adult and females will continue to lay eggs on other leaves. The galls are more of a cosmetic damage and because your hickory leaves will fall from the tree as winter comes, the galls will normally not cause enough damage to worry about each year. Once again good cultural practices and disposal of each year’s leaves will reduce the gall numbers next year.
In a large tree with many leaves, foliar feeding by beetles and caterpillars do cause damage though the leaves will still produce enough food (photosynthesis) to keep the tree alive. Most of us never climb our trees to look at leaves to see the small insects/mites and there are more than enough leaves to maintain tree health.
The biggest concern during my site visit was their tree’s bacterial infection. A knife blade was pushed into the wound area and went in less than 1/4″. The homeowner was instructed to look at bactericide applications. In the end, this hickory tree with so many problems is still shading the home and helping cool the house. It is still giving refuge to wildlife and beneficial insects. When in doubt give our trees the benefit and keep them in place. Remember your local Extension agent is set up to make site visits and saving a tree is time well spent.
Growing Key Limes in the home landscape is not only a fun and unique addition, but is also delicious – any way you slice them.
The key lime, Citrus aurantifolia, originated in southeast Asia. Genetically speaking, the key lime is likely a tri-hybrid cross between the “odd ball fruits”, known as citron, pummelo and a microcitrus species, Citrus micrantha. There is little commercial key lime production nowadays in Florida, but the fruit remains a very popular landscape option.
The key lime is a small, bushy tree that makes harvest and pruning a breeze. Like most citrus, it’s self-pollinating. The key lime is also an ever-bearing fruit, so there is no real seasonal harvest. The tree could technically bloom any month of the year. There are very few varieties, as trees mostly come from true seed or air layering.
Key Lime fruit at various degrees of ripeness. Photo courtesy of Ray Bodrey, UF/IFAS Extension Gulf County.
Climate is an important factor when deciding to plant a key lime. They are sensitive to cold temperatures, especially below freezing. For the Panhandle, it’s wise to keep key lime trees as patio citrus. In other words, keep the trees in pots so that they can be moved indoors for protection during the winter months. In the ground, trees should be planted in an area where there is a significant wind block. Once a few years have passed and tree has become more mature and acclimated to the environment, they may be able to survive on their own, though it is recommended to cover the tree under sub-freezing temperatures. However, it is important to remember that sunlight is a catalyst for citrus fruit production, be sure to plant the tree in an area with full sun.
The usual suspects of citrus insect pests apply to the key lime also. Citrus leaf miner and mites are the most common culprits. Horticultural and insecticidal oils will certainly help to combat these threats. For planting, key lime is well adapted to a variety of soil conditions in Florida. Be sure to water newly planted trees every other day for the first week and then one to two times a week for the first couple of months. Water periodically after that, making sure the soil doesn’t stay completely dry for long periods. A 6-6-6 fertilizer works great for the key lime. Please follow the fertilizer schedule found in the UF/IFAS EDIS publication, “Citrus Culture in the Home Landscape” by Robert E. Rouse and Mongi Zekri: https://edis.ifas.ufl.edu/pdf/HS/HS132/HS132-11822781.pdf
A final interesting thing about the key lime is the ripening stages of the fruit. Because key limes are ever-bearers, blooms can develop at sometimes widely varying times. This causes an uneven development of fruit across the tree. Be sure to wait until the fruit turns begins to turn yellow before harvest. That’s when it’s mature to eat! Fruit can be stored for up to a week in the fridge or can be juiced and stored in the freezer for later use.
Please contact your local county Extension office for more information. Happy Gardening!
Information for this article can be found in the UF/IFAS EDIS publication, “Key Lime Growing in the Florida Home Landscape” by Jonathan H. Crane: https://edis.ifas.ufl.edu/publication/CH092
UF/IFAS Extension is an Equal Opportunity Institution.
Photos by Sheila Dunning
The showy chaste tree makes an attractive specimen as the centerpiece of your landscape bed or in a large container on the deck. Much more of them are being seen since the Florida Department of Transportation has recognized the tree as a desirable median planting. Easy-to-grow, drought resistant, and attractive to butterflies and bees, Vitex agnus-castus is a multi-stemmed small tree with fragrant, upwardly-pointing lavender blooms and gray-green foliage. The chaste tree’s palmately divided leaves resemble those of the marijuana (Cannabis sativa) plant; its flowers can be mistaken for butterfly bush (Buddleia sp.); and the dry, darkened drupes can be used for seasoning, similar to black pepper, making it a conversation piece for those unfamiliar with the tree.
Vitex , with its sage-scented leaves that were once believed to have a sedative effect, has the common name “Chastetree” since Athenian women used the leaves in their beds to keep themselves chaste during the feasts of Ceres, a Roman festival held on April 12. In modern times, the tree is more often planted where beekeepers visit in order to promote excellent honey production or simply included in the landscape for the enjoyment of its showy, summer display of violet panicles.
Chaste tree is native to woodlands and dry areas of southern Europe and western Asia. It will thrive in almost any soil that has good drainage, prefers full sun or light shade, and can even tolerate moderate salt air. Vitex is a sprawling plant that grows 10-20 feet high and wide, that looks best unpruned. If pruning is desired to control the size, it should be done in the winter, since it is a deciduous tree and the blooms form on new wood. The chaste tree can take care of itself, but can be pushed to faster growth with light applications of fertilizer in spring and early summer and by mulching around the plant. There are no pests of major concern associated with this species, but, root rot can cause decline in soils that are kept too moist.