by Daniel J. Leonard | Jan 10, 2018
Are you guilty of “Crape Murder”, the dreaded horticultural sin that involves lopping off your beautiful Crape Myrtles fence post high and creating gnarly looking knuckles? No need to raise hands, you know who you are! Despite the cruelness of this act, all is not lost; there is still time to repent and change your ways! The facts of the matter are, if you have made a habit of lopping the tops off your crapes, you are most definitely not alone, you probably thought you were doing the right thing, and it can be corrected.
Improper pruning of crape myrtles. Photo Courtesy – Beth Bolles.
Crape Myrtle (Lagerstroemia spp.) are one of the most beautiful trees Southerners have in their horticultural arsenal. Unsurpassed in both form and flower, it is easy to see why Crape Myrtle is the most widely planted tree in the Southeastern United States. A mature Crape Myrtle properly grown is a remarkable sight, sinewy limbs reaching high in a vase shape supporting lilac-like flowers that come in a rainbow of colors. These qualities make it even more strange that homeowners and landscape professionals alike insist on butchering them every winter.
Before we move on to corrective procedures, let us examine a few of the reasons that crape murder is committed. First, I think peer pressure has a lot to do with it. When one sees every house on the street and all the business landscapes doing things a certain way, one tends to think that is the correct way. Second, there are folks who believe that pruning their crapes back each year creates a superior flower show. In reality, this practice creates an overabundance of succulent, weak, whippy branches (with admittedly larger flowers) that tend to bend over and break after a summer wind or rainstorm and are more prone to pests and disease. In addition, many homeowners over prune their crapes in this way because they planted a cultivar that grows too large for the site. There are dozens of crape myrtle cultivars sold, be mindful to pick one with a mature size and shape that will fit with the scale of the site!
So, now that we know why crape murder is committed, let’s discuss how to remedy it once the atrocity has already occurred.
- If the improper pruning has not been going on very long (a couple of years or less), it may be possible to correct over time without taking drastic measures. If this is the case, select two or three of the young “whippy” canes that are growing up and out and remove the rest. Ideally, the canes you select will be growing away from the center of the plant and not back into the middle of the plant or straight up to facilitate proper branch spacing as the tree continues to grow. The canes you select now will become primary branches in the years to come, so plan and prune carefully. Repeat for each main trunk that has been “murdered”. You will have to keep watch on the cut areas, as they will attempt to regrow as suckers after pruning; simply remove these juvenile shoots until they stop emerging.
Properly pruned crape myrtle. Photo courtesy – North Carolina Cooperative Extension
- If the murder has been going on for more than a year or two, it likely cannot be corrected without a major rejuvenation of the plant. Though it will likely be painful for you emotionally and seemingly run counterintuitive to your instincts, the best method to rejuvenate a disfigured crape is to break out the chainsaw and cut the plant back to the ground! This forces the plant to do one of two things; either grow an outrageous number of new shoots or die. In most cases however, the crape myrtle’s tough constitution permits it to regrow from the stump. The first growing season after performing this procedure, allow the shoots that sprout to grow and do not prune. The winter following the first growing season, remove all except three to five strong, well-spaced shoots and allow these to become the new plant’s main trunks. In all succeeding years, only prune to remove dead wood, crossing branches and branches growing toward the center of the plant.
If you have been guilty of crape murder, it is not too late to change your ways! Follow these steps, get out and enjoy the cool weather, and get to correcting your mistakes while the plants are still dormant! As always, if you have any questions about the topic of this article or any other horticultural topics, please contact your local Extension office and happy gardening!
by Sheila Dunning | Dec 14, 2017
Photo by Sydney Park Brown UF/IFAS
Holly has been considered sacred in some cultures because it remained green and strong with brightly colored red berries no matter how harsh the winter, even when most other plants would wilt and die. According to Druid lore, hanging the plant in homes would bring good luck and protection.
Later, Christians adopted the holly tradition from Druid practices and developed symbolism to reflect Christian beliefs. Today, the red berries are said to represent the blood that Jesus shed on the cross when he was crucified. Additionally, the pointed leaves of the holly symbolize the crown of thorns Jesus wore on his head.
Several holly species are native to Florida. Many more are cultivated varieties commonly used as landscape plants. Hollies (Ilex spp.) are generally low maintenance plants that come in a diversity of sizes, forms and textures, ranging from large trees to dwarf shrubs.
The berries provide a valuable winter food source for migratory birds; however, the berries only form on female plants. Hollies are dioecious plants, with male and female flowers on separate plants. Both male and female hollies produce small white blooms in the spring. Bees are the primary pollinators, carrying pollen from the male hollies 1.5 to 2 miles, so it is not necessary to have a male plant in the same landscape.
Several male hollies are grown for their compact formal shape and interesting new foliage color. Dwarf Yaupon Hollies (Ilex vomitoria ‘Shillings’ and ‘Bordeaux’) form symmetrical spheres without extensive pruning. ‘Bordeaux’ Yaupon has maroon-colored new growth. Neither cultivar has berries.
Hollies prefer to grow in partial shade but will do well in full sun if provided adequate irrigation. Most species prefer well-drained, slightly acidic soils. However, Dahoon holly (Ilex cassine) and Gallberry (Ilex glabra) naturally occur in wetland areas and can be planted on wetter sites.
For a more comprehensive list of holly varieties and their individual growth habits refer to ENH42 Hollies at a Glance: http://edis.ifas.ufl.edu/mg021
by Matt Lollar | Nov 20, 2017
Sometimes you don’t realize a tree is dying until it is dead. A few weeks ago, we got a call from a client who said he had insects killing his trees. Before having someone drive out to the property, our Master Gardener volunteer recommended that the client bring in some of the insects for us to take a look. It turned out the insects invading his pine tree were a type of longhorned beetle, but more specimens were required for identification. A site visit soon ensued.
There were a number of pine trees on the property, however only one was infested with the insects in question. Upon closer investigation, we noticed a number of different sized holes in the tree. The larger holes are nearly the size of a dime.
Arrowhead borer damage on a pine tree. Photo Credit: University of Florida/IFAS Extension.
It turns out the insects making the larger holes are a type of longhorned beetle known as an arrowhead borer (Xylotrechus sagittatus). The borers are brown to black in color with a reddish hue. They are moderately hairy and some specimens contain arrowhead markings pointing toward their heads. Adults feed on the bark of damaged or fire-killed pines. The adults are attracted to lights and may be mistaken for crickets because they run very fast. Eggs are laid in bark and larvae feed on sapwood, then tunnel deeper, often tunneling within a single annual ring. The borers pupate inside the tree and the newly emerged adults chew their way out.
Arrowhead Borer. Photo Credit: Tom Murray bugguide.net.
Given the fact that arrowhead borers are attracted to dead or dying trees, the killer of this particular tree is still in question. The smaller holes in the bark picture above were created by a much smaller beetle, but we were unable to get a specimen. We did see a couple of these beetles running around when we dug deeper into the bark. The small beetles that we saw closely resembled a type of Ips engraver beetle. Beetles in this genus have been known to kill trees, but most likely they weren’t the culprits either. Based on the overall appearance of the tree and the fact that other trees in the area were not infested with beetles, it is believed the tree was killed by other means. The tree was likely struck by lightening or suffered from poor genetics because it did not have a good form for a pine tree.
If you have a questionable looking tree on your property or if you have insects you would like identified, please feel free to stop by your local Extension Office and ask a Master Gardener!
by Julie McConnell | Oct 23, 2017
Cypress twig galls on bald cypress leaves. Photo: J_McConnell, UF/IFAS
Bald cypress Taxodium distichum is a native tree that is commonly planted in landscapes because it is adaptable to many sites and grows quickly. It is an interesting tree because it has soft flat leaves that fall off in the winter like other deciduous shade trees; however, it belongs to the Cypress family which consists mostly of needled evergreens.
Like the other cypresses, bald cypress produces cones in the fall, which is a primary means of reproduction for the species in natural settings. During the same season that cones are maturing, you might also see what looks like cones forming at the tips of branches among the leaflets rather than along the stem. These mysterious growths are not cones but rather twig galls.
Bald cypress twig galls are abnormal growths of leaf bud tissue triggered by the attack of the cypress twig gall midge Taxodiomyia cupressiananassa. In late spring, adult midges lay eggs on new leaves of the bald cypress. As the eggs hatch and midge larvae start feeding on the bald cypress leaves the growth of a twig gall is induced. The larvae take advantage of this gall using it for food and shelter throughout the larval stage and into the pupal stage. After pupation, adults emerge from the galls, mate, and females lay an average of 120 eggs over a two-day lifespan as an adult. This first generation lays eggs on mature leaves which starts the cycle again. The galls formed by the second generation of the year fall off and overwinter on the ground.
The galls do not appear to affect the health of trees overall, although the weight of heavily infested branches may cause drooping. There are many natural enemies of the twig cypress gall midge, so applying insecticides are not recommended since they may cause harm to non-target insects. The simplest management option is to collect and destroy the galls in the spring and fall to reduce populations the following season.
To read more about bald cypress trees or the twig gall please see the following publications:
by Beth Bolles | Oct 23, 2017
Trees are a landscape asset for many homeowners. When a new tree is installed in our landscapes, we can’t wait for it to mature to provide shade or landscape interest. The heartbreak for many homeowners comes when this important part of their landscape, begins to decline five to ten years after establishment. We often consider a pest as the cause. The common culprit is often hidden below the mulch and soil and is easily preventable.
When larger specimen trees are installed in residential and commercial landscapes, they may be delivered with materials that help hold the rootball in place. Strapping often runs over the rootball and when trees are young is several inches away from the trunk. Installers or homeowners often do not cut the strapping during installation.
As this tree continue to grow, the rootball straps will interfere with normal trunk development. Cutting the straps takes only a few seconds at the time of planting. Photo by Beth Bolles, UF / IFAS Extension Escambia County
Over the years, tree trunks will grow in diameter and eventually reach the strapping. Because the strapping is still firmly in place, it can cut into a growing tree, resulting in girdling. Although many trees try to overcome the injured area by forming new wood over and around the girdling, this is a major stress that interferes with water and food movement in the plant. What we see is a tree that may be slower to leaf out in the spring, a thinning canopy, and twig dieback. These symptoms may be confused with another cause since the strapping is normally hidden from view.
The crape myrtle on the right has a very thin canopy. Investigation found a severe area of girdling from strapping left uncut at planting. Photo by Beth Bolles, UF / IFAS Extension Escambia County.
If you do have a tree that exhibits the above listed symptoms, it never hurts to look at the trunk and root flare just below the mulch and soil surface. If you find strapping still in place, cut it so that it is loose. Depending on the severity of the problem, this may not save the tree but it is worth a try on your important investment.
by Mark Tancig | Sep 18, 2017
Hopefully, by this time of year, most north Florida gardeners have harvested their figs and are enjoying fig preserves or fig bars. But if you’ve noticed your fig leaves dropping a little early, it may be a sign of the fungal disease Fig Rust (Cerotelium fici).
Figs are a great fruit tree for the north Florida home garden. Not only do they provide a tasty reward (if you can keep the birds and squirrels away), but they are fairly easy to maintain and are bothered by relatively few pests and diseases. One of the few diseases that can be common, however, is fig rust, especially when conditions are favorable. In the case of fig rust, a fungus, warm humid weather is what it likes and well, we have plenty of that.
Figs are a great fruit tree for North Florida. Credit: Mary Derrick, UF/IFAS.
The first signs of the fig rust disease are small yellow to yellow-green spots/lesions on the upper surface of the leaf that turn a reddish-brown color as they get larger. A heavy infestation causes the leaves to turn yellow and drop early. While fig rust does not injure the fruit, repeat occurrences of premature leaf drop can adversely affect the overall health of the tree, resulting in yield loss. Another concern is that if the leaves drop too early, the tree will flush out with new growth heading into winter. This new growth can be injured by early freezes and cause a loss of fruit the following season.
Fig rust on leaves. Credit: UF/IFAS.
What can you do to prevent and/or cure fig rust? Unfortunately, once you see the yellowish-green/reddish-brown spots on the leaves, it’s too late to provide any control. As always, proper cultural practices can help. Pruning the tree to provide adequate airflow keeps the leaves as dry as possible during our humid summers. Remember to prune fig trees in Florida after fruit harvest, not in the dormant season, since fruit is borne on previous year’s growth. Another cultural control to prevent fig rust is to rake diseased leaves out from under the tree. The fungal spores in the fallen leaf litter pass the disease on to next year’s leaves. Other cultural controls include providing adequate moisture and placing a healthy dose of mulch around the tree. Figs require minimal fertilizer. Using a general complete fertilizer with micronutrients (such as a 10-10-10), young trees should receive 1 cup (1/2 pound) and mature trees 4-8 cups (2-4 pounds) per year.
There are currently no chemical controls approved for fig rust in Florida. The classic Bordeaux mix is recommended by various authors to be used as a preventative fungicide during the dormant season, before the lesions appear on the leaves. The Bordeaux mixture is a mix of copper sulfate, lime, and water in a 1:1:10 ratio and is considered an organic pesticide. This mix has been used since the late 19th century and was discovered by accident after botanists and farmers realized that grapevines sprayed with the mix to deter theft had less fungal problems. As with any pesticide, be cautious when using. Overuse of copper-based fungicides can cause copper to build up in soils, leading to potential issues to plant and human health.
While figs are generally worry free for our area, fig rust is one disease to be on the lookout for. Good gardening practices can reduce the occurrence of this disease and ensure a bountiful harvest. For questions on growing figs or about the fig rust disease, visit the UF/IFAS EDIS website – edis.ifas.ufl.edu – or contact your local Extension office.
Photo by Sydney Park Brown UF/IFAS
