Extended spring weather with cool nights and frequent rain can be enjoyable for humans, but does strange things to plants, especially if dormant fungi are hanging around. Exobasidium vaccinii is a fungus that is believed to overwinter as spores attached to bark and bud scales. It can cause infection with the opening of buds in spring, creating odd shaped leaves and flowers that are referred to as galls. Infection is dependent on high humidity and moisture during bud break. Gall growth is due to plant cell division resulting from the stimulus of hyphal growth within host tissue. When galls are still soft, the fungus grows between epidermal cells, breaks the cuticle, and sporulates giving the gall a white cast. Either all or part of a leaf may become thickened, fleshy, and covered with a white bloom of spores. At first, diseased leaves are succulent and white, but they later shrink into hard, brown, gall-like bodies. Galls are composed of fungus-infected plant tissue. Older leaves are resistant to infection. Exobasidium vaccinii is most common in azaleas and camellias.
Photo by Sheila Dunning
But, other Exobasidium species are floating out there, and with just the right conditions they can deform other plants. That’s what caused this odd formation on one flower of a gardenia plant. In this case, the spores fused the sepals to the petals of the flower.
Photo by Margaret Stewart
While chemical controls are available, they would need to begin before symptoms appear and continue until the gall dried completely. It may be an option for the fastidious weather watcher with a good working knowledge of this disease. But, for the rest of the population, removing and destroying galls before they turn white is the best management practice to avoid having spores form and hang around until next spring. Proper pruning of the plants to improve air circulation will also reduce the chances of favorable conditions, should there be an extended cool, wet season next year.
Florida’s natural areas—a great source of pride and enjoyment to its citizens—provide recreation, protect biodiversity and fresh water supplies, buffer the harmful effects of storms, and significantly contribute to the economic well-being of the state. Unfortunately, many of these natural areas can be adversely affected by invasive plant species. An estimated 25,000 plant species have been brought into Florida for use as agricultural crops or landscape plants. While only a small number of these have become invasive, Chinese tallow (Triadica sebifera) is one of them.
As the trees begin to turn various shades of red, many people begin to inquire about the trees. While their autumn coloration is one of the reasons they were introduced to the United States, it took years to realize what a menace the trees become. Triadica sebifera, the Chinese tallow is locally referred to as popcorn tree due to the appearance of the developing seed heads, white three-chambers seeds covered in a fatty wax. It was introduced to Charleston, South Carolina in the late 1700s for oil production and use in making candles. However, the seeds are also tasty snacks for birds and can float long distances in the water, enabling it to spread to every coastal state from North Carolina to Texas, and inland to Arkansas. In Florida it occurs as far south as Tampa, displacing other native plant species in those habitats. Therefore, Chinese tallow was listed as a noxious weed by the Florida Department of Agriculture and Consumer Services Noxious Weed List (5b-57.007 FAC) in 1998, which means that possession with the intent to sell, transport, or plant is illegal in the state of Florida.
Fall color of Chinese tallow
Individuals can help mitigate the problem of Chinese tallow trees in Florida’s natural areas by removing them from their property. Mature trees should be felled with a chain saw by the property owner or a professional tree service. The final cut should be made as close to the ground as possible and as level as possible to facilitate application of an herbicide to prevent sprouting. Stumps that are not treated with an herbicide will sprout to form multiple-trunked trees. If it is not objectionable for dead trees to be left standing, certain herbicides can be applied directly to the bark at the base of the tree (basal bark application).
Herbicides that contain the active ingredient triclopyr amine (e.g., Brush-B-Gon, Garlon 3A) can be applied to cut stumps to prevent re-sprouting. The herbicide should be applied as soon as possible after felling the tree and concentrated on the thin layer of living tissue (cambium) that is just inside the bark. Herbicides with the active ingredient triclopyr ester can be used for basal bark applications. Only certain triclopyr amine products may be applied to trees that are growing in standing water. If trees are cut at a time when seeds are attached, make sure that the material is disposed of in such a way the seeds will not be dispersed to new areas where they can germinate and produce new trees.
Space in a landscape left after removal of Chinese tallow can be used to plant a new native or noninvasive tree for shade, or some other landscape purpose. Although Florida is not known for the brilliant fall color enjoyed by other northern and western states, there are a number of trees that provide some fall color for our North Florida landscapes. Red maple, Acer rubrum, provides brilliant red, orange and sometimes yellow leaves. The native Florida maple, Acer floridum, displays a combination of bright yellow and orange color during fall. And there are many Trident and Japanese maples that provide striking fall color. Another excellent native tree is Blackgum, Nyssa sylvatica. This tree is a little slow in its growth rate but can eventually grow to seventy-five feet in height. It provides the earliest show of red to deep purple fall foliage. Others include Persimmon, Diospyros virginiana, Sumac, Rhus spp. and Sweetgum, Liquidambar styraciflua. In cultivated trees that pose no threat to native ecosystems, Crape myrtle, Lagerstroemia spp. offers varying degrees of orange, red and yellow in its leaves before they fall. There are many cultivars – some that grow several feet to others that reach nearly thirty feet in height. Also, Chinese pistache, Pistacia chinensis, can deliver a brilliant orange display.
There are a number of dependable oaks for fall color, too. Shumard, Southern Red, and Turkey are a few to consider. These oaks have dark green deeply lobed leaves during summer turning vivid red to orange in fall. Turkey oak holds onto its leaves all winter as they turn to brown and are pushed off by new spring growth. Our native Yellow poplar, Liriodendron tulipifera, and hickories, Carya spp., provide bright yellow fall foliage. And it’s difficult to find a more crisp yellow than fallen Ginkgo, Ginkgo biloba, leaves. These trees represent just a few choices for fall color. Including one or several of these trees in your landscape, rather than allowing the popcorn trees to grow, will enhance the season while protecting the ecosystem from invasive plant pests.
For more information on Chinese tallow tree, removal techniques and native alternative trees go to: http://edis.ifas.ufl.edu/ag148.
When beautyberries start producing their eye-catching, bright purple fruit in late summer, we start to get lots of questions. People want to know what it is, where can they find it, and can they eat it? While the berries look good enough to eat, it’s best to leave them to the birds and deer. They are not toxic and were used by Native Americans for a root tea to treat fevers, stomach aches, malaria, and more, but the taste has been described as bitter and mealy. Thanks to a generous volunteer, I am lucky enough to have tried beautyberry jelly. A little (or a lot) of sugar can make most anything taste good—and the finished product is a beautiful, translucent shade of fuchsia.
Homemade beautyberry jelly is a real treat for breakfast! Photo credit: Carrie Stevenson, UF IFAS Extension
Even more interesting to me was the revelation that researchers have been able to extract compounds from beautyberry that successfully repel pest insects such as ticks and mosquitoes. The study began about 15 years ago, after a Mississippi botanist with the USDA Agricultural Research Service mentioned to a colleague that his grandfather taught him to rub the crushed leaves of beautyberry on his skin. The technique had been used as a home remedy to prevent mosquito bites for people (and horses) for generations. As a follow up experiment, another group of researchers found these same compounds—callicarpenal and intermedeol—successfully repelled black-legged ticks (which transmit Lyme disease) as effectively as DEET. In the last few years, researchers out of Mississippi have worked towards creating natural insect repellents from the compound that are less harsh on human skin that many commercially available brands.
The striking purple berries of the beautyberry shrub attract the attention of people and wildlife, alike. Photo credit: Carrie Stevenson, UF IFAS Extension
Aside from its many practical uses, Callicarpa americana is a beautiful native shrub. It has wide green leaves and the brilliant purple berries grow in clusters along its stem. They stay on through late fall and winter in some places, making a beautiful contrast to fall foliage. Beautyberry shrubs can be found in a wide variety of habitats, including sandy and wet soils, full sun, and part shade. Their adaptability makes them a great plant for tight conditions like roadsides or yard edges, but also for nearly any home landscape. The plants can grow to a height of 4-8 feet and spread 3-6 feet wide. The long-lasting berries make them a great wildlife food source later in the cool season than many berry-producing species.
The flower of the Christmas season is the poinsettia, a tropical plant from Mexico that changes its leaf color when the daylength changes. Poinsettias were originally noticed for their bright red color and are now available in many colors, shapes and sizes, thanks to decades of work by plant breeders. As much as we love them, caring for poinsettias during and after the holiday can be a challenge. Here are a few tips to extend the bloom for a longer period and encourage it to grow for the months to come!
Photo credit: Tyler Jones.
Provide plenty of sunlight. A sunny window facing south is ideal. Be careful to not let the leaves touch the glass. Keep temperatures around 55-60F at night and 65-70F during the day.
Keep soil slightly moist on the surface. Wait until the surface feels dry before watering, then add just enough to soak in. If water collects below the pot, pour it out. Those decorative wrappers make it hard to tell, so be sure to check. However, don’t wait for wilting before watering as that is too dry. Both overwatering and underwatering can lead to wilting and excessive leaf drop. Check the soil each day.
Don’t fertilize while “blooming”. While the colored parts of poinsettias are actually modified leaves called bracts and the true flowers are the tiny yellow centers, we often refer to the entire non-green portion as a bloom. The plant can maintain its nutritional needs throughout the flowering time without additional fertilizer.
In the spring, cut the plant back, fertilize and move outside. Remember, poinsettias require temperatures to always stay above 60F. If we receive any cool nights, bring it in for the night. Let the rootball become quite dry throughout April. You may have to move it under a cover if the April showers are occurring every few days.
If you want to try your luck at re-blooming, re-pot it in a slightly larger container and cut it back to about 4” high in mid-May. Keep it in nearly full sun. A little shading in the heat of the day is helpful. Water consistently and fertilize every two weeks with a water-soluble, complete fertilizer. As it grows, you will need to pinch the plant back every six weeks or so until October, I usually remove about half of the stem that has grown out. To get coloration in time for Christmas, find something dark to cover the plant or move it to a dark location each day. The poinsettia must be in complete darkness from 5 p.m. to 8 a.m. until the leaves start to turn color, usually 10 weeks. That means moving or covering and uncovering at the same time every day. Any deviation will delay the color change. Once you see a complete set of leaves coloring, the plant can be exposed to regular daylengths. If this sounds like too much work, spent poinsettias do make good compost and garden centers will be happy to sell you a new one!
Remember, poinsettia sap does contain a latex-like chemical that can cause allergic reactions. Small animals, young children, and adults with allergies should not handle poinsettias. If eaten, get medical attention immediately.
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.
Do any of the leaves change color down here in the fall? The most common answer is that there is none here in the land of evergreens. The prevalence of oaks (Quercus spp.) and pines (Pinus spp.) see to that. There is hope. Deciduous trees put on a show as the need for photosynthesis reduces. Chlorophyll production stops replaced with anthocyanins and carotenoids. As they take over, the beautiful display we all love begins. Several tree species thrive in the panhandle and have great autumn foliage. Once you know which, you’ll see a color pallet that would make DaVinci himself drool.
Tree for all seasons
Sweet gum (Liquidambar styraciflua) is a larger tree growing upwards of 75 feet tall with a 50 foot spread. The canopy has an early conical shape which evolves into an oval as the tree ages. This tree is excellent for local parks and to provide shade in your front yard. Red tinged flowers produced in spring combined with multi-shaded leaves provide interest throughout the year. However, autumn this tree comes into its own. As the days shorten and cool these leaves begin their journey to the ground by taking on shades of yellow, orange, red, or burgundy.
IFAS photograph Heather Kalaman
Panhandle Delight
A unique tree growing primarily in the Panhandle, the Florida maple (Acer floridanum) puts on an excellent autumn show. At that time of year, the leaves will change to a muted yellow or orange color. Reaching 60 feet high and 30 wide this oval canopied tree is ideal for shade or along streets. Fall is the only time you will see color changes from this tree, but in summer you’ll be treated to that classic maple leaf shape.
IFAS Photograph
An Oddity of a Tree
The bald cypress (Taxodium distichum) is a tree rife with oddity. Growing at times as high as 80 feet with a roughly 35 foot spread these trees excel in your lawn. Be wary as when grown in wet environments they develop “knees” thought to help aerate roots in standing water. Ball shaped cones are the primary reproductive organs of this tree. For the purposes of this article, we’ll focus on the color changing needles. When winter is nigh, they change from pale green to an eye catching yellow or rusty copper. One of the few deciduous conifers, the needles will fall off revealing peeled bark for winter interest.
IFAS Photograph Kathy Warner
To Sum it Up
These are but a few of the trees in north Florida known to change color in the autumn. The list is not overly exhaustive, but there are several in this category. For more information on landscape trees, see this Ask IFAS document, or contact your local extension agent for additional information on this and any topic regarding your gardens and more.
