An interesting phenomenon turned up in my camellia this spring. What has, for years, been a perfectly normal bush – growing its glossy, dark green leaves year ‘round and its showy flowers in the fall – suddenly changed. Its leaves started becoming variegated!
Symptoms of Camellia Yellow Leaf Mottle Virus.
Variegation refers to different colored areas of plant tissue. Most commonly, a plant will have stripes or patches of white leaf tissue along with the normal green. Sometimes, colors can vary or the placement can include stems or fruit. Many cultivated varieties of ornamental plants are selected for these interesting patterns, and sometimes food crops as well. A novel, attractive pattern can make for a very profitable plant. In the 1630s, the price of variegated tulips skyrocketed for several years in the Netherlands. During this period of ‘tulip mania’, a single tulip bulb could potentially sell for ten times the annual income of a skilled artisan. Imagine paying $200,000 for one flower!
A variegated variety of star jasmine, propagated for its coloration.
Some variegations are caused by genetic mutations. Plants that are chimeras have cells with different genetic makeups. These varieties must be propagated by cutting or grafting to preserve both sets of genes. Even if successfully propagated, sometimes individual leaves or branches of these plants might lose one color or the other. A leaf that is completely white won’t thrive; it contains no chlorophyll, which gathers energy from sunlight. A leaf that becomes completely green may outcompete the rest of the variegated plant, leading to a loss of variegation over time.
A randomly occurring genetic mutation in Florida pusley, a common weed of lawns.
Other variegations, such as those Dutch tulips and my camellia, are caused by viruses. Most are not desirable, as they decrease the health of the plant even if they don’t kill it outright. Others will quickly lead to decline and death. A mosaic virus, for example, might make your tomato leaves look interesting, but it will eventually kill the plant. In the case of a camellia, ‘camellia yellow leaf mottle virus’ is usually transmitted during the propagation or grafting process, whether intentionally or not. Camellias affected by this virus are usually not harmed, though a lack of chlorophyll in leaves leads to less energy for the plant to use in growth and producing flowers. Still, sometimes the tradeoff for fancy foliage is worth it!
Some branches on variegated plants may turn completely white (or green).
My camellia must have received a bug bite that transmitted the virus, as I haven’t done any grafting on it. I’ve noticed a few others nearby with similar symptoms. If you see this starting on your plant, you may be able to prune out the affected area before it spreads. Make sure to sanitize pruning equipment with alcohol between cuts, and dispose of infected material if you do remove it. For other unwanted viruses, the solution may be a bit more extreme. If you cannot prevent infection in the first place through sanitation and insect control, disposal of the entire plant is often the only option that will keep the virus from spreading to other nearby plants. For any plant disease or pest issue, scout regularly and address the issue before it becomes too big. Consult your local Extension office for information or check out our EDIS publications on specific topics at https://edis.ifas.ufl.edu/.
After a relatively cold winter like the Florida panhandle has experienced the last couple of years, it’s always gratifying to see plants greening up in the spring. Anyone who enjoys the outdoors is likely to want to get out there and start helping things grow. That means it’s time to get the irrigation system up and running every day, right?
Probably not!
The conditions in our region can be harsh on plants. The soils are very sandy, meaning they don’t easily hold on to water or nutrients for plants to use. The weather ranges from freezing cold in the winter to sizzling hot in the summer. Rain might come down in 20-inch bursts or not at all for weeks at a time.
With all these challenges plants face, it’s very important to choose ones that can handle all that our environment throws at them. Native plants and those designated as “Florida Friendly” tend to be well suited for our location, but they still may need some care. They must be placed in the correct location in the landscape based on their needs for sunlight, water, and other factors. If you choose the right plant and place it in the right location, you’ll drastically reduce the amount of management that it needs on an ongoing basis. This includes watering.
While actively growing, plants – whether that means towering trees or low-growing grass – take up water through their roots and give some off in the form of water vapor through their leaves. If the amount of water in the soil is more than the plant is giving off, it doesn’t need more! Watering at these times can actually harm, rather than help. The roots of overwatered plants typically start to die back, which can lead to symptoms such as patchy dieback of foliage or what may look like nutrient deficiency. Overwatered areas might also see an uptick in water-loving weeds such as dollarweed, which will be difficult to control unless the area is dried out a bit.
Set irrigation systems to water early in the morning rather than at midday, and make sure they water plants, not walls.
It is tempting to think that our sandy soils drain quickly enough to make watering a constant necessity, but remember! We’ve already chosen plants that survive well in our location. Even our turfgrasses are chosen for their ability to withstand drought. There may only be three or four months out of a year that become dry enough to warrant extra irrigation at all, and even then, it’s probably less than most people expect!
For lawns, a general rule is to water only when the grass is showing signs of drought stress. Leaf blades may fold up lengthwise, the lawn’s color may become duller, and footprints in the turf persist rather than springing back. If the turf needs watering, apply ½ to ¾ inch of water per irrigation – that’s all!
Improperly calibrated irrigation systems can do more harm than good.
To figure out how much that is, set several small, empty straight-edged cans such as cat food tins or tuna cans out in the lawn. Run the irrigation for a set period of time to see how much water collects. This will also highlight any inconsistencies in watering, so you can try to adjust your irrigation system to water evenly by replacing broken nozzles and making sure the whole area is covered with no gaps or overlaps. Make sure the irrigation system is equipped with a rainfall shutoff device as well, to automatically stop watering when it rains (which it often does regularly).
Overwatered shrubs may display patchy dieback or yellowing leaves.
For landscape plants such as trees and shrubs, you may not need any supplemental irrigation at all unless there is a severe drought. Know your plants’ needs and keep an eye on the weather. Droughts, if we do have them, usually occur in the spring or fall in our area. During the summer, daily rainstorms often allow us to keep our irrigation systems off for months at a time!
Water appropriately and you may notice a reduction in your water bill, fewer plants that need to be replaced, and fewer water-loving weeds. You’ll also help the environment by reducing runoff into water bodies.
For more information on watering, contact your local Extension office. There is also a wealth of information to be found online, with resources such as the Florida Friendly Landscaping program and UF’s EDIS publications (see “Watering Your Florida Lawn”, for example). Happy watering!
On occasion, homeowners report being troubled by certain slimy visitors to their gardens. Perhaps not the first pest most people would think about in their landscapes, snails are nonetheless a source of frustration for some. While many species are harmless or even beneficial, some can make a nuisance of themselves by munching on plants, or even just congregating in large numbers.
Just sighting a snail is not always cause for alarm. Snails are gastropods, a type of mollusc that is closely related to slugs. Snails may be found in the water or on land, and terrestrial species are often seen in areas where moisture is plentiful. Many feed on decaying organic matter, doing the important job of breaking down dead material in the environment. Others may eat living plants, and can cause consternation when they chew holes in the leaves of vegetables or ornamentals. A few may even act as predators, such as the native rosy wolf snail, which attacks other snails.
Farmers have found difficulty in dealing with Bulimulus sporadicus, a species introduced from the West Indies. This species is often found in moist areas, and seems to prefer feeding on decaying plant matter rather than live plants. However, it is prolific and gregarious, with large populations appearing on walls, fences, irrigation emitters, and on plants. Peanut growers may have difficulty screening the shells, which are around the same size as a peanut, from their harvest. Growers relying on irrigation to water their crops may find nozzles clogged by snails seeking out moisture. And homeowners may find their homes polka-dotted with dozens of these little creatures.
When snails get together, it may be an alarming sight. Bulimulus sporadicus doesn’t seem to damage plants, but does like to congregate. Photo credit: Danielle Sprague
If you are having trouble with snails, consider trying to reduce areas of higher humidity that they may shelter in. Mulch, dead vegetation, or weedy areas can all hold moisture, making happy homes for slugs and snails. While it may be difficult or almost impossible to control humidity, denying pests their shelter can help to keep them away.
Commercial repellents are available. Copper fungicides may protect plants from fungal diseases as well as leave residues that snails find distasteful. Hydrated lime or sulfur dust at the base of plants can repel snails, though be aware that they may have an effect on the pH of the soil if used in large amounts, or over time.
Traps can be of some help in reducing snail populations. A dish with steep sides, sunk into the ground and baited with something attractive, may be able to trap snails in it. Beer, fruit, or leafy greens like lettuce can work, though they may also attract raccoons or other animals.
Some baits containing molluscicides may also be available, but these may or may not be effective.
Migratory animals are no stranger to our neck of the woods. Every year, Florida is host to countless creatures as they make their way from one place to another in search of food, nesting sites, or just a change of scene. From hummingbirds to manatees, it can be interesting to watch the annual cycle of nomadic animals.
A gulf frittilary butterfly.
One of the smaller wayfarers we see year-round, but especially when they migrate south in the fall, is the gulf frittilary butterfly, Agraulis vanillae Linnaeus. They spend the warmer months of the year in the southeastern United States, following frost-free weather as temperatures drop. During the winter, they enjoy the sunshine of peninsular Florida.
The gulf frittilary is a medium-sized butterfly, with a wingspan of 2½–3½ inches. Females are larger than males. It is bright orange in color, with black markings on the top of its wings and silvery-white spots on the bottoms. In its larval form, it is also bright orange in color, with dangerous-looking spines along the length of the caterpillar. Despite their appearance, these do not sting.
The gulf frittilary caterpillar looks dangerous, but won’t sting. Please do not eat it, however.
If given a choice its larvae will feed primarily on passionflower (Passiflora incarnataand related species), but have also been seen snacking on buttonsage. Toxins from passionflower concentrate in the larvae and butterflies, making them poisonous to predators – much like the monarch butterfly and its host plant, milkweed. The insect’s bright coloration serves as a warning that it is not to be eaten.
Keep an eye out for these beautiful butterflies and consider planting a passion vine in your landscape to help them out. The caterpillars may eat the leaves, but in giving them a feast you’ll help them grow into adult butterflies. Once they do mature, they are fantastic at pollinating many of our native wildflowers, further beautifying the world around them.
For more information see the University of Florida’s article here.
Throughout the year, people with citrus trees of any sort may notice some damage to the leaves. Chewing damage, which leaves pieces of the leaf missing, is a common sight. The likely culprit for this type of damage is an insect that is very common in our area, but seems to have multiple personalities!
The adult form of this peculiar creature is the giant swallowtail butterfly, Papilio cresphontes Cramer. A large black-and-yellow butterfly, it is found throughout the country east of the Rocky Mountains, and is present in north Florida most months of the year. Adults spend their days as many other butterflies do, flitting from flower to flower in search of nectar. They are attracted to a wide variety of blossoms, pollinating as they go.
The giant swallowtail butterfly. Photo courtesy of Donald Hall, University of Florida
Females lay tiny round eggs individually on the surface of plant leaves. Though their larvae may eat numerous types of leaves, one of their favorites seems to be those of citrus trees. This means that though the adults may be considered beneficial as pollinators, their caterpillars are often thought of as pests.
Bird poop or caterpillar? The orange dog caterpillar is, in fact, a caterpillar.
Similarly, the beauty of the adult butterfly is quite different than the appearance of their younger selves. The caterpillar of the giant swallowtail, often called the ‘orange dog’ caterpillar, relies on camouflage to keep itself safe. Even with this it displays multiple personalities, so to speak. Larvae of any age may be mistaken as bird droppings on a leaf. Their irregular patches of white and brown make them look like the leavings of a passing avian, which predators are probably likely to pass over. Older caterpillars have another trick up their sleeve, with markings on their head that mimic the head of a snake. Disturb one enough and it may even flash a forked, bright orange protuberance called the osmeterium, which may resemble the tongue of a snake. This gland also emits a musky odor to make the insect even less attractive to potential predators.
Snake or caterpillar? The osmeterium might look like a snake’s tongue, but don’t be fooled. Photo courtesy of Donald Hall, University of Florida
Whether wearing a beautiful, ugly, or scary face, these insects are here to stay. Thankfully, they don’t often do enough damage to citrus trees for homeowners to worry about. Young trees in danger of being defoliated may need some protection, but an established tree can lose a leaf or three with no issues.
If control is called for, hand-picking the caterpillars is a viable option, as long as the tree is small enough to reach the branches. A product called Bt, short for Bacillus thuringiensis, is another option. Applied to the leaves, this insecticide only affects caterpillars, and shouldn’t harm other pollinators.
