Normal fall leaves on deciduous crape myrtle. Credit: Larry Williams
Imagine you’re a leaf on a deciduous tree. In spring, you emerge and are blemish-free. You experience the first rays of light. You’ve never existed before. You begin to photosynthesize. This is what green leaves do. You’re normal.
The first windstorm occurs in April, blowing you into other leaves, branches and stems. You sustain a puncture wound. Trees don’t heal. So, any damage is permanent.
In May, a small population of aphids dine on the tree’s leaves. Ladybugs consume most of the aphids and a blowing rain dislodges the remaining few.
During the extended hot, dry weather of June and July, the tree’s owner is not watering properly and the tree begins dropping leaves. This is a normal process in many tree species during periods with insufficient moisture.
But you stay firmly attached.
The tree’s owner overdoes it in fertilizing his lawn and burns some of the tree’s leaves as a result. Most tree roots are shallow, having access to lawn fertilizer. Your leaf margin becomes brown and crisp as a result.
In August, you’re exposed to direct sunlight all day, partly because of the longer day length and partly because of the loss of other leaves that once shaded you.
In September, the tree’s owner applies weed and feed to his lawn. Tree roots growing in the lawn pull up some of the herbicide.
Tree roots grow two to three times beyond the branches, having access to herbicides applied to adjacent lawn areas. The herbicide injures many of the leaves, including you.
Shorter days and cooler temperatures of fall bring on changes in your physiology. The green pigment chlorophyll that has allowed you to produce sugars through photosynthesis since you first emerged is now breaking down.
As a result, your green color fades and fungal spots, sun scald and the puncture wound from spring become visible.
During October and November, many neighboring leaves turn loose and fall to the ground. This is part of the normal senescence process on deciduous trees.
Before you fall, the tree’s owner notices that you don’t look so good and becomes concerned about your brown spots instead of the uniform green color you had in spring. He has visions of another dead tree and rushes to his County Extension Office carrying you in hand.
A Master Gardener Volunteer explains to the tree’s owner that the spots are a natural part of the senescence process. The leaf is at the end of its life.
The tree’s owner is provided information on proper tree care.
The following spring, the tree produces new, healthy leaves, is provided better care and lives happily ever after!
Despite being a near-perfect ornamental for the Panhandle, Crape Myrtle is often misused. Though there are dozens of commercially available varieties in all shapes and sizes, many people choose the wrong one for their yard. The most commonly sold cultivars ‘Natchez’ (white flowers), ‘Muskogee’ (pink flowers), and ‘Tuscarora’ (watermelon red flowers) – all three attain mature heights more than 20’ – are almost always too large for siting near a house or other structure and are often out of scale with landscapes. The simple solution to making the best use of Crape Myrtle in smaller yards (certainly not dramatic pruning – Crape Murder is among the worst landscape sins), is to select a smaller growing variety and ‘Tonto’ is a personal favorite in this category.
‘Tonto’ Crape Myrtle, one of the selections that emerged from Dr. Don Egolf’s Crape Myrtle breeding program at the U.S. National Arboretum over 50 years ago, is among my favorite Crape Myrtle varieties for several reasons. First, Tonto’s fuchsia hued flowers are as vibrant as flowers come; they practically glow in the landscape. The flower show lasts for several months and are a valuable food source for pollinators, bees in particular, in the late summer when few things are blooming. Tonto also is a relatively slow grower that only reaches about 10’ tall and wide at maturity. This allows the variety to be exceedingly versatile in landscapes as it can be used in the background of planting beds, as a specimen plant, limbed up as a small tree in open areas, or even placed in very large containers. Finally, beyond just the flower show and ideal size, ‘Tonto’ has uniquely attractive, cream colored, exfoliating bark and reliably attractive fall foliage. Both these features add interest to landscapes, even when ‘Tonto’ isn’t flowering.
Though ‘Tonto’ sports many unique qualities, it shares many other excellent traits and growing preferences with its Crape Myrtle kin. For best results growing any Crape Myrtle, trees should always be sited in full sun, at least 6-8 hours a day. Shading will result in greatly reduced flowering and lanky plants. Regular watering during the first year after planning while trees are becoming established is helpful, as is periodic fertilizer application. Once established, ‘Tonto’ and all other Crape Myrtles are exceedingly drought tolerant and can get by on their own with minimal inputs from gardeners.
If you’ve been struggling with a Crape Myrtle that has outgrown its site or thinking about planting a new Crape, I’d encourage you to give ‘Tonto’ a look. It’s an outstanding shrub/small tree, will reward you with flaming fuchsia flowers and smooth cream-colored bark each summer, and will never outgrow its space. Plant one today! For more information on growing Crape Myrtles or any other horticultural topic, contact us at the UF/IFAS Calhoun County Extension Office. Happy gardening.
Being a gardener in Florida is exciting. We have many plants to choose from and the weather is mostly pleasant but always seeming to surprise us. One disadvantage of living in such a place, in addition to having so many growing zones, landscape nurseries, and major shipping ports, is that invasive species that land in Florida don’t like to leave. One newcomer in the lineup of invasive pests is the crape myrtle bark scale (Acanthococcuslagerstroemiae). This invasive insect pest made its way from Texas and, as of a few weeks ago, the only Florida sighting had been in Santa Rosa County. Unfortunately, this pest has now been confirmed in Leon County. Landscapers and gardeners in north Florida should learn how to identify this pest and what options are available for control.
The crape myrtle bark scale, as the name suggests, has a pretty specific host – the crape myrtle (Lagerstroemia spp.). However, in the United States, this scale has also been found feeding on our native beautyberry (Callicarpa americana). Due to the widespread planting of crape myrtles, these should be the gardeners primary focus when looking for this new pest. If present on the tree, it is hard to miss. These scales feed on the bark and are a snow-white color. Being a scale, they produce honeydew that is then covered in black sooty mold. So, if you see a crape myrtle with black branches, look closely and you may see the white scales. If you crush these scales and they leave a pink goo on your fingers, then you very likely have crape myrtle bark scale. Of course, you can send a picture or sample to your local county extension office for confirmation.
Black sooty mold and white scales along the trunk and branches are a tell-tale sign of crape myrtle bark scale. Credit: Mark Tancig, UF/IFAS.
If you do happen to find crape myrtle bark scale in your own landscape, or one that you manage, proper control is important to prevent it from moving along any further. Since scales suck on sap and are protected by an outer shell, systemic insecticides are the preferred product for effective control. These include the neonicotinoids, such as imidacloprid (Merit) and dinotefuran (Safari). The larval stage can be controlled with a horticultural oil, sometimes mixed with another insecticide like bifenthrin (Talstar), however, this will not control the adults. Another option is to completely remove the tree and burn all of the plant material.
Excessive sooty mold has turned these branches black. Be on the lookout for crape myrtles looking like this to help identify crape myrtle bark scale. Credit: Jim Robbins, Univ. of Ark. CES. Retrieved from bugwood.
The crape myrtle bark scale can significantly reduce the aesthetic value of crape myrtles due to the black sooty mold that covers the bark. It is also known to reduce flowering and can lead to thinning of leaves. Since crape myrtles make up a big part of our managed landscapes, let’s all work together to scout for this pest and control it when found. If you have questions, please contact your local county extension office.
Difference in flowering due to crape myrtle bark scale damage. Credit: Jim Robbins, Univ. of Ark. CES. Retrieved from bugwood.
The shorter days and cooler temperatures of autumn bring on changes in our shrubs and trees.
Most people expect to see changes in leaf color in deciduous trees and shrubs during fall. But some people become concerned when the leaves on certain evergreen plants begin to turn yellow with the change in the seasons. For many plants this is normal.
Azaleas may lose a few leaves now. These are the older leaves on the branches near the center of the plant. There is no need for alarm by the loss of a few older azalea leaves from now until spring. However, if the younger leaves, those nearest the tip of the shoot, turn yellow or brown there is cause for concern. Poor drainage, lack of water or alkaline soils may cause this condition. Be sure to keep azaleas and other ornamental plants well-watered during dry weather that may occur from now through spring.
Other plants such as gardenias, hollies and camellias may have yellowing leaves now. But as with azaleas, these are the older leaves on the stem near the center of the plant. The mature leaves will drop from the plant from now until spring. This is only the normal aging of older leaves. However, be careful to not confuse this normal process with spider mites, scale, lace bugs, nutrient deficiencies, poor growing conditions or salt injury. Just keep in mind that this normal change in leaf color and leaf drop occurs on the older leaves generally during cooler weather – it’s a seasonal change.
Young red maple with fall foliage. Photo credit: Larry Williams
The leaves of sycamore trees have changed from green to brown by now. Although the sycamore is a deciduous tree, this phenomenon may not be caused by a change in day length or temperature alone. This change in leaf color in sycamores can begin in late summer. Many times, it is the result of sycamore lace bugs feeding on the leaves. By the time the damage is visible, there is little that can be done to correct the problem. However, this problem will take care of itself since sycamore trees will soon be dropping their leaves.
We do have some trees that exhibit beautiful fall foliage this time of year. A few to consider include hickory and gingko for their bright yellow fall foliage, black gum for its early display of brilliant red, purple or orange leaves and Chinese pistache for its late reddish-orange fall show. There are plenty of other good trees to consider for fall color here in North Florida such as dogwood, crape myrtle, Florida maple, sourwood, shumard oak and the list could continue.
Crape Myrtle season is almost upon us. Soon, every roadside, landscape, and gas station parking lot in the deep south will be lit up in gaudy colors from white to hot pink to fire engine red. A well-placed Crape Myrtle (Lagerstroemia hybrids) can turn even the most boring landscape into a picturesque photo op once summer rolls around. These toughest of flowering trees also ask very little of gardeners to look their best, thriving in many varied settings with a wide range of care given to them. Despite their low-maintenance nature, I see all too many Crape Myrtles languishing in landscapes. While it is difficult to fail with Crape Myrtles, it is not impossible if you site and maintain the trees incorrectly. This summer, follow these three tips to get the most out of the best small tree a southern landscape can offer.
Properly sited, pruned, and maintained crape myrtle. Photo courtesy of Daniel Leonard.
Do not murder your Crape Myrtles. For any reason. No other tree gets lopped off each year to a random height in the belief that it makes it prettier. While your “murdered” crape may indeed produce more flowers the following season, you are permanently damaging the tree, giving rot and decay a foothold, unnecessarily making the tree more susceptible to storm damage, and ultimately shortening the tree’s lifespan. The only pruning that should be done to the species is an occasional “limbing-up” to expose the gorgeous flaky bark underneath and to remove dead or dying branches.
Don’t plant Crape Myrtles in shade. Crape Myrtles perform their best in 6+ hours of blistering full sun per day. Even light shade at various times during the day will greatly reduce flowering, cause the tree to appear thin, and force it to reach for the sun, creating a leggy look. There are many wonderful small landscape trees like Greybeard, Redbud, and Japanese Magnolia that make excellent Crape Myrtle alternatives in shady sites. If you can’t put a Crape in full sun, plant something else.
Keep the area under the canopy free of turfgrass. Turf is a wonderful feature in lawns, just not directly under crape myrtles. Grass does an excellent job of scavenging nutrients and water that otherwise would benefit the crape myrtle above. Also, having grass inside the dripline forces homeowners and landscape professionals to cut the grass right up to the trunk. This often leads to soil compaction from heavy mower traffic and damage from lawnmower decks and string trimmers, which damages the thin Crape Myrtle bark and can even girdle and kill the tree. Either kill out the grass and weeds under the canopy with a nonselective herbicide like Glyphosate and then mulch or plant a shade loving groundcover like Asiatic Jasmine.
Crape Myrtle is one of the most rewarding plants Panhandle gardeners can grow as well as one of the easiest. By following just a few best practices, not overpruning, planting only in full sun and keeping the ground free of turfgrass under the canopy, pretty much every landscape can enjoy success with the species. For more information on growing Crape Myrtle and other gardening topics, reach out to your local UF/IFAS County Extension office! Happy Gardening!
