William Afton, Singh, Raghuwinder, Strahan, Ronald E., Timmerman, Anna, Fontenot, Kathryn, Kirk-Ballard, Heather
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Some of the most gifted plants at the end of the year are holiday cacti. Even if the name is not familiar, most people recognize the characteristic look of holiday cacti. They are seen all throughout the houseplant sections of garden centers and home improvement stores during the holiday season. Perhaps you have been given one as a gift or given one to someone else.
All cacti are members of the family Cactaceae, which contains about 127 different genera and over 1,750 different species. The vast group can be broken down into two different types. When most people think of cacti they think of the desert-dwelling plants loaded with spines. These cacti are correctly termed “desert cacti.” However, there is a second group of cacti that grows on trees in tropical and subtropical forests. “Forest cacti” are known as epiphytes, which are plants that grow on other plants for support but are not parasitic. Because of this nature, forest cacti prefer partial shade locations. Holiday cacti are members of the forest cacti group. Both groups are native to the Americas.
Holiday cacti include both the Christmas cactus (Schlumbergera truncata) and the Easter cactus (S. gaertnerii). The orchid cactus (Epiphyllum ackermanii) is also grouped together with the holiday cacti. To distinguish Christmas cacti from Easter cacti, look at the flat stems that make up the shoots. Most of us may call these flattened stem segments leaves, but botanically speaking, cacti do not have leaves. The modified stems of cacti are filled with chlorophyll, hence the green color. They act just like the leaves in other plants. The flattened stem segments of Christmas cacti have a distinctive toothed edge, whereas Easter cacti exhibit a scalloped edge. The two virtually look the same except for time of year when they flower.
To properly care for Christmas cacti, it is important to understand their native environment. These plants originated from the jungle region of the Western Hemisphere. As previously stated, they grew within the canopies of large trees. Do not place your cacti in an area that receives a lot of direct sunlight. Choose a location that receives bright but filtered light. An area with an eastern or southern-facing window should work well. Watering these cacti will be a little different that watering a desert-type cactus. Christmas cacti will need more water, but be careful not to keep the soil wet. Wet soils will contribute to root rot and poor plant health. Instead, irrigate the plant until water drains out the bottom of the pot. Check the soil from time to time until you feel it completely dry from the tip of your finger to the first knuckle. This will indicate when to water the plant again. Use a water-soluble fertilizer in the spring and summer to provide essential plant nutrients. A few insect problems may arise during the growing season. Applications of horticultural oil will provide adequate control.
One of the biggest issues facing Christmas cacti is second and subsequent year blooming. The plants available for sale at plant nurseries come out of commercial greenhouses and are forced to bloom heavily at the holiday season. The new owner of a Christmas cactus will need to do a few things to ensure blooms in the following season. The typical flowering season for Christmas cacti is from November to January. Once flowering has finished let the plant rest. Keep it cool and back off on watering. After about eight weeks you can start treating it like normal, providing water when the soil becomes dry. During the summer months you can move the plant outside to a filtered light location. Early fall is a crucial time for flower bud production. Back off on watering and keep it cool. You might even want to move the plant to a cooler location. When flower buds form you can return to regular watering practices. Be careful not to overwater during this time. Stressful conditions may result in aborted flowers. The plant should start blooming again late fall through the first of the year. Enjoy and show it off for all to see. Then start the process over again.
County Agent, St. Tammany Parish
Camellias are a beautiful part of our landscapes this time of year, providing cool-weather blooms while all of the tropicals look brown and fried. While most camellia maintenance takes place after flowering, one pest is on the move and needs to be scouted for and kept under control now.
Tea scale is an insect that likes to feed on and infest the underside of camellia, sasanqua and Burford holly leaves. The scale insects are concealed underneath a cottony white material while the actual insects are small, brownish grey and scabby in appearance. They feed by sucking the plant juices and can cause a lot of damage, and even death, if left untreated. There are armored and unarmored species of scale insects that attack camellias, Fioriniae theae being the one commonly referred to as tea scale. Female scale insects are able to reproduce every one to two weeks, increasing the population exponentially.
Newly hatched scale insects are called crawlers and are able to move about the plant to colonize new sections. Crawlers can also move to new plants using the wind by flying a silk kite. Insecticides are much more effective when used to treat the crawlers, which typically emerge in the spring. In our area, they emerge in February or mid-January depending on the temperatures. Treating camellias and other tea scale-infested plants with oil should be done in this time frame. Spray the entire plant, top to bottom, including the underside of the leaves with neem oil or horticultural oil. Systemic insecticide products also work well at this stage and control crawlers as well as adult scale insects. Contact insecticides can work but are much less effective than oil treatments or systemic insecticides.
Adults can also be smothered now by using a light horticultural oil. To treat, mix light horticultural oil with some warm water in a ratio of 1 part oil to 1 part warm water. Use a sponge or rag to wipe the oil onto the scale on the undersides of the leaves. Be sure to thoroughly coat the scale, really wetting and saturating the cottony material and the scabby insects themselves. Typically this treatment works with one pass, but you may need to reapply in a week. Dead scale insects turn a darker shade of brown or black and easily flake off of the underside of the leaf. Live scale insects are fairly moist, while ones that have died are dry to the touch.
There are several generations of tea scale crawlers each year, so monitor your plants weekly to catch any new outbreaks. Catching the issue early is the best way to avoid heavy infestations that can lead to camellia death. Heavily infested shrubs should be monitored and treated as needed and may require several years of control. Pruning out heavily infested branches or leaves can help. Increasing air circulation within the plant helps to open the insects up to natural predators, such as lacewings, ladybugs and spiders. Be sure to move or protect these natural allies when treating tea scale.
Greater New Orleans Horticulture Agent
Tiny scale insects can be seen hiding on the underside of the leaves.
Photo by Chris Dunaway
Everyone has no doubt begun decorating for the holiday season. You’ve got your excited folks who started listening to Christmas music and threw up the decorations before the Thanksgiving holiday. (Hey, no judgment here.) Then you’ve got the folks like me who put the tree up the weekend after Thanksgiving. And some of us are busy and are just now getting around to it.
No matter what type of holiday decorating you do, there is one thing anyone can do very inexpensively by using what is just outside your door. You can create an evergreen wreath or swag with a few inexpensive floral materials and plant cuttings from the landscape.
The materials you will need to complete the project include fresh floral foam (3 inches by 4.25 inches by 3.25 inches) and a commercially made wire cage or one you create with a wire clothes hanger. You also need waterproof floral tape, 24-gauge wire (or similar) and 4-inch wire wood picks (optional). The tools you will need are pruning shears, wire cutters and a pocketknife or grafting knife.
Then you’ll need to gather an assortment of evergreen materials from the landscape. They could include cedar, camellia, evergreen wisteria, gardenia, holly, juniper, laurel bay, Leyland cypress, nandina, magnolia, mahonia, pine, pittosporum, sweet olive and wax myrtle. And don’t forget all the Christmas tree trimmings.
You also can go to a local nursery or box store selling fresh-cut Christmas trees and get the trimmings from such trees as blue spruce, Fraser fir, noble fir and Nordmann fir. They smell wonderful, and these plant materials offer several textures to incorporate into your wreath or swag.
Hollies such as American, Burford, English, Foster’s, Savannah, Winterberry and yaupon are excellent selections to help incorporate red berries. Another common landscape plant — nandina — also displays red berries in the wintertime.
If you use a commercially prepared cage of fresh floral foam, you can get started right away. However, you can make your own by securing a wire hanger around a cube of fresh floral foam. Add a water-impermeable material, such as contact paper, to the back of the foam to prevent water damage. Secure the backing and foam to the hanger using the waterproof tape in a tic-tac-toe pattern with two vertical lines and two horizontal lines encompassing the hanger and foam brick.
Hydrate the floral foam with water before beginning to add plant materials. This takes about 30 seconds. If you want your live cuttings to last longer, be sure to hydrate the foam several times a week. Next, begin placing greenery in the foam. You can use longer materials in the top and bottom for a swag or place the greenery equally in a circular pattern for a wreath look.
At this point make a fresh cut on the stem of the greenery itself by using a utility knife to create a sharp point. Cut down the bottom half of only one side of the stem as if to whittle away the bark. Now, stick this into the foam. Or you can wrap the wire on a 4-inch pick around the bottom half of the stem for stability and stick the stem and pick together into the foam.
Longer pieces such as fir, Leyland cypress and pine are great to use on the top and bottom of the swag. Then use more pieces to fill in both sides of the foam. This creates the skeleton, so to speak.
Then you may begin to fill in the piece with different textures, such as magnolia, camellia and holly. Finally, install the “centerpiece” — typically something with red berries, pinecones or a festive bow. You can secure the pinecones and bow using the wired picks or lengths of wire by wrapping and twisting the wire through the cones’ scales or around the center of the bow.
Create a swag by elongating the design, making the top and bottom longer and the sides of the piece shorter. For a wreath look, keep all the plant materials similar in length along all sides. You may use the hanger to hang on the door or the grommets or holes already in place on the commercial foam.
Voila! You have a DIY wreath that cost next to nothing. I’ve seen designs that retail for $50 to $100. Save that money to do some Christmas shopping or share with someone in need this holiday season. Merry decorating. It’s a fun activity for all!
Consumer Horticulture Specialist
All joking aside, 2020 has not been a grand year. There are things we can and cannot control, and we have to roll with life’s punches. Nevertheless, we can control many things in our garden. So, let’s make the most of December’s garden and start the new year off right by following best management practices to get the most out of our fruit and vegetable crops.
A beautiful head of cabbage.
December is the last month I think of as actual winter. January and February to me are very early spring. So, in this last month of winter here are a few to-do items to help keep the garden active!
Dr. Kathryn Fontenot
Vegetable Crops Specialist
December begins a bleak time for warm-season turfgrasses. Most lawns should be dormant or at least close to this stage by Christmas. Because lawns are not actively growing, fertilizer applications are not needed during the winter. Actually, you should have stopped nitrogen fertilization on home lawns by late summer (late August to very early September for St. Augustine grass and centipedegrass).
Nitrogen fertilizer on dormant to semidormant St. Augustine grass, centipedegrass and zoysia grass lawns can lead to increased brown patch and winter kill. Also, nitrogen applications during this time have a greater potential for leaching or movement into nontarget areas.
Winter is an excellent time to collect soil samples and submit them for analysis. Samples should be a composite of soil collected from 3 to 4 inches deep at various places around the lawn. Mix well and reduce the sample to about 1 pint of soil and take it to the LSU AgCenter Extension Service office in your parish or to a participating garden center. Make sure to specify the type of grass you are growing on the soil test form.
Soil samples submitted to the LSU AgCenter result in a wealth of information concerning the overall fertility of your soil. If results of the soil test indicate the soil pH is too acidic, lime will be prescribed in the soil test recommendations. Sulfur may be prescribed for soils that are too alkaline. Winter is the best time to apply lime or sulfur so that it can be activated by for the growing season next spring and summer. The correct soil pH is extremely important and has everything to do with nutrient availability and fertilizer performance.
Postpone any permanent warm-season turfgrass seeding until next spring. Soil and air temperatures will be too cold for germination and growth.
Sod, such as St. Augustine grass and centipedegrass, can be laid during winter and established successfully during the spring. But remember to maintain good moisture to prevent the sod from dying. Establishment of sod is easiest, however, when sodding is delayed until the middle of spring, well after spring green-up.
Large patch disease, which was once known as brown patch, can come and go throughout the winter if the weather is mild. Treatment with fungicides containing myclobutanil, propiconazole, pyraclostrobin, and triticonazole and azoxystrobin will reduce the spread of large patch. Damage from large patch will slow spring green-up, and diseased areas will remain unsightly until warmer spring weather conditions help with turfgrass recovery. These diseased areas are more prone to weed problems.
Broadleaf weeds, such as clover and lawn burweed (sticker weed) and annual bluegrass infesting St. Augustine grass, centipedegrass and zoysia grass, and dormant bermudagrass, can be suppressed with a late fall application of atrazine herbicide followed by a winter application. The window for these atrazine applications is from November to early March. Herbicides containing a three-way mixture of 2,4-D; dicamba; and mecoprop (trimec-type herbicides) can be used for winter broadleaf control on the same lawns that were sprayed with atrazine. MSM (metsulfuron) works well on lawn burweed and is highly effective on clovers and false garlic. Weed-and-feed products can be substituted as your first application of fertilizer during the early spring.
Lawns may show signs of green-up in southern Louisiana in late February. Do not push turfgrass growth with fertilizer at that time! Fertilizer applied too early will feed winter weeds and will result in lush turfgrass growth that is more susceptible to injury from late frosts and increased levels of large patch disease. Lawns may be fertilized in the New Orleans area by late March, but delay fertilizing central Louisiana lawns until April. Consider fertilizing lawns in north Louisiana around mid-April.
Dr. Ron Strahan
Turfgrass Science and Weed Science Specialist
Wild geranium is a common winter broadleaf infesting lawns.
Lawn burweed germinates in the fall and produces painful stickers in the spring.
Catchweed bedstraw is a sticky winter weed that attaches to pants and pets.
Many homeowner and commercial landscapers are noticing clusters of mushrooms appearing in their landscapes. These mushrooms are fruiting bodies of Armillaria root rot caused by Armillaria spp. It is a destructive disease of a wide variety of woody ornamentals, trees, shrubs and fruit trees. Common host plants include roses, camellias, azaleas, crape myrtles, bottle brush, jasmine (confederate), Chinese elms, oaks, pines, Leyland and Italian cypress, apples, peaches, pecans and others. The disease is generally attributed to Armillaria mellea; however, several different species of Armillaria are capable of causing root rot. In the southeastern United States, A. tabescens is primarily responsible for causing the disease.
Symptoms caused by this disease are similar to those caused by other root rot pathogens. Infected plants wilt, rapidly decline and eventually die. Leaves turn yellow and defoliate. In some host species, the entire foliage turns brown. A white fungal mycelium is usually present underneath the bark at the base of the stem and the roots, which can be easily seen by removing the bark. In severely infected shrubs or trees, the white mycelium extends into the crown region, and even a few feet up on the trunk. Clusters of honey-colored mushrooms commonly appear at the base of infected plants or around it in the fall.
Armillaria tabescens is a soil-borne fungal pathogen normally associated with hardwood forests. It may survive in the soil on infected roots for several years. Disease can be more problematic in urban landscapes that are created on previously wooded areas. The pathogen becomes active when roots from a new tree or shrub come in contact with old infected roots. The disease spreads from one plant to another through root-to-root contact or by the growth of the fungus through the soil by means of fungal structures called rhizomorphs.
There is no cure for this disease. Once a host plant is infected and the fungus is established, little can be done to save it. No chemicals are available to control this disease. However, there are culture management practices that may help to either avoid or reduce the impact of this disease. Start with disease-free healthy plants. Do not plant them too deep. Completely remove and discard plants suspected to be infected with A. tabescens. Careful removal of the stumps and roots along with significant amounts of soil from previously infected sites may help reduce the fungal inoculum. Avoid planting susceptible hosts in the same locations where infected plants were previously removed. Water thoroughly and deeply and as infrequently as possible without causing drought stress. Avoid continuous wetting of the base and crown region of the plants, which favors the growth of the fungal pathogen. Use of excessive mulch (mulch mounds) around the base of the plant should be avoided to keep the crown region dry. Follow a proper fertilization program.
Suspected host plants infected with A. tabescens can be submitted to the LSU AgCenter Plant Diagnostic Center for confirmation. For more information, please visit our website: www.lsuagcenter.com/plantdiagnostics.
Dr. Raj Singh
Plant Pathologist and Director of Plant Diagnostic Center
Italian cypress showing browning of entire canopy as a result of root rot caused by Armillaria root rot.
Photo by Raj Singh, LSU AgCenter
Bottle brush showing white fungal mycelium extended 2 feet up on the trunk.
Photo by Raj Singh, LSU AgCenter
Cluster of honey-colored mushrooms produced by Armillaria sp.
Photo by Raj Singh, LSU AgCenter