The term “ornamental grass” is a catch-all phrase used to describe grasses and “grass-like” plants. Individual species are adapted to a wide variety of landscape sites (i.e., wet or dry, sun or shade, hot or cold climates, and varied salt tolerance). Growth habits range from low ground covers to intermediate shrub-like plants to very tall hedge-like plants. Ornamental grasses are very dynamic; the size, shape, texture, and color of grass changes with every season.
Deciduous Ornamental Grass
Grasses with foliage that dies in the winter and remains dormant until the weather warms in the spring are considered deciduous. The winter character of deciduous ornamental grasses adds tremendous interest to the winter garden when contrasted with evergreen plants or structures such as walls or fences. The dried foliage of deciduous grasses creates sound as it expands and contracts in response to changes in temperature or moisture, while interaction with wind creates movement in the garden. For these reasons, pruning of the dead foliage and inflorescences is not recommended at the time of the first frost.
Pruning of ornamental grasses should be done in late winter or early spring, just prior to new shoot growth. In Northwest Florida, gardeners should target the end of February to prune ornamental grasses. For deciduous grasses, such as Japanese silver grass (Miscanthus sinensis), the old foliage may be completely removed within inches of the soil. Be cautious to not remove the growth point by leaving the grass clump at least 4 inches high. For evergreen grasses, such as muhly grass (Muhlenbergia capillaris), the ragged leaves can be removed to neaten the appearance of the plant without shortening all the way to the ground. So, depending on the damaged portions, the remaining grass clump can be 6-18 inches high after pruning. Grasses recover quickly from a heavier pruning. Within a few months the plant will have completely regrown. If desired, old flower stalks and seed heads may be removed any time they no longer have a neat appearance. For more information on ornamental grass species and growing tips, please visit the EDIS Publication: Considerations for Selection and Use of Ornamental Grasses.
Frost on Dune Sunflower
Picture by: Pam Brown
December is finally here and that means consistent nights of watching for dropping temperatures. Tropical plants and newly installed shrubs are susceptible to cold injury. Those colorful, blooming plants that have added a tropical look to the landscape all summer may begin to suffer when the temperatures drop below 500 F. Leaves may turn yellow and flowering stops. These plants will need to be moved inside or have temporary greenhouse built around them. But, hardy plants that haven’t established a sufficient root system will also need additional attention when the temperatures drop dramatically.
The ability of plants to endure a freeze depends on the species and the weather leading up to the extra cold night. Gradual decreases in temperatures helps plants acclimate to winter. But, a sudden one day drop of 40-50 degrees results in a rapid freeze that causes ice to form inside the plant cells. Leaf and stem tissue expands so quickly that it splits, resulting in parts of the plant incapable of transporting water and nutrients, as well as, performing photosynthesis. However, it may be late the following spring before the damage is noticed, when that section of the plant has slowly staved to death.
Cracked bark from frost
Additionally, plants can experience desiccation or drying out. This happens when dry winds and solar radiation result in the loss of more water from the leaves than can be transported by a cold root system. The resulting symptom is marginal and/or tip burning of leaves that leads to totally brown leaves.
Freezes (when the temperature drops to 320 F) are characterized as radiational or advective. Radiational freezes occur on calm, clear nights when heat radiates from the surfaces of plants, making them colder than the air due to the rapid loss of heat. If there is moisture in the air, ice will also form on the surfaces. Under these conditions, ice forms between plant cells, rather than within the individual cells. Most hardy plants can tolerate these type of freezes if they are properly hydrated.
Advective freezes occur when cold northern winds move in rapidly, dropping temperatures quickly, and causing widespread foliage desiccation. Cultivation and maintenance practices can impact a plant’s ability to endure extended periods of low temperatures. Shade-tolerant species installed under the canopy of a tree typically display less injury from radiational freezes because the trapped heat from the ground and the overhead foliage creates a microclimate. Well-watered soil around a plant will absorb solar radiation during the day and re-radiate heat over night, raising the temperature around the plants. Shrubs that are not pruned in the late summer or fall have leaves that can withstand frost and wind. But, the removal of foliage late in the growing season triggers a flush of new growth, that is very sensitive to lower temperatures. The same response can result from fertilizer applications after plant’s have slowed down in growth.
Irrigation Frost Protection on Citrus
Picture by: Univ of Maryland Extension
So, what can you do to prepare for upcoming freezing temperatures? Begin by avoiding pruning and fertilizing at the end of the season and making sure that the plants have been watered within 24 hours of a cold night. Next, insulate against water loss and increase heat radiation by adding a three-inch of mulch, as well as, covering the trunks of sensitive trees with a commercial tree wrap. Then, consider what needs to be covered. Frost cloth or other breathable fabrics can trap heat for the night and provide a protective layer from frost settling on the leaves. It needs to be placed by mid-afternoon and removed the next day when temperatures are above 320 F. Plastic is not recommended unless the timing regime can be followed reliably and a structure is used under the material to keep the plastic off the foliage. Anchoring of the cover is critically important in the event of an advective freeze.
Finally, turn off the sprinkler system. Commercial agriculture often uses a running irrigation system to keep the leaf surface temperatures near, but not below, 320 F because sprinkling utilizes latent heat released when water changes from a liquid to a solid state. The thin layer of ice melts and re-freezes on the surface throughout the night, without ice forming within the plant tissues. For the technique to work, sprinkling must begin as freezing temperatures are reached and continue until thawing is complete. Landscape systems are not designed to deliver the amount of water over the length of time required to accomplish this type of frost protection.
When the cold nights have passed, don’t forget to check your plants for water. But, wait until winter has passed before pruning out the frost damaged stems.
Photo by Kathy Warner
UF/IFAS Master Gardener – Nassau County
With their shiny green leaves, compact growth habit and unique blooms, camellias are the winter queen of flowering shrubs. Worldwide, there are about 250 different species of camellias. In the landscapes of Northwest Florida, the most commonly grown species are Camellia sasanqua, Camellia japonica and hybrids of these. Collectors and botanical gardens may have Camellia reticulata, Camellia hiemalis, Camellia vernalis and hybrids of multiple species. The young leaves of another camellia species, Camellia sinensis, are processed for tea, one of the world’s most common beverages. The various species of camellia plants are generally well-adapted to acidic soils, especially those rich in organic material. Camellias requires consistent watering, particularly once the flower buds are set. Most species prefer protection from direct sun during the heat of the day and will bloom well in significantly shaded areas. Individual species and cultivars bloom seasons vary with growing climate. Camellias are classified by their blooming time, ranging from early to late season, relative to other camellias. For extended flowering, plant a variety of cultivars. Early-fall bloomers begin in October and re-bloom through January. Long-bloomers add a few months with flowers from November to April. Camellias that start opening in January and continue through March are referred to as mid-season bloomers. Spring blooming camellias are the last to flower, from March to May. When deciding on particular cultivars also consider the various flower shapes. There are six flower forms, with changes in number of petals and appearance of stamens. Camellias do come with a few potential pest problems. For information refer to: https://gardeningsolutions.ifas.ufl.edu/care/pests-and-diseases/pests/camellia-pests-and-problems.html
COVID 19 has resulted in many cancelled events. But, you may find a local camellia show to see some the fantastic blooms of many different cultivars. Here are a few options:
December 12, 2020
Pensacola Camellia Club, University of West Florida, Conference Center & Ballroom, 11000 University Parkway, Building 22, Pensacola, FL, Skip Vogelsang, (850) 776-7951, firstname.lastname@example.org
January 10, 2021
Northshore Camellia Club, Southern Hotel, 428 E. Boston St., Covington, LA, Show Chairman: Hunter Charbonnet, email@example.com, Contact, Judges’ Chair & Show Reporter: James Campbell, firstname.lastname@example.org, (985) 630-9899,
January 16, 2021
Ozone Camellia Club, Slidell Municipal Auditorium, 2056 Second Street, Slidell, LA, Show Chairman: Jim Campbell, email@example.com, Show Contact: Bruce Clement, (985) 259-5527, firstname.lastname@example.org, Show Reporter: Stella Allen,
January 23, 2021
Camellia Club of Mobile, The Shoppes at Bel Air, 3299 Bel Air mall.,Mobile, AL 36606, Show Chairmen: Walter Creighton & Larry Heard, email@example.com, Show Contact: Larry Heard, (251) 661-9392, Judges’ Chair: Jim Smelley, Show Reporter: Jim Dwyer,
Sheila Dunning is the Commercial Horticulture Agent with the University of Florida Extension Service in Okaloosa County. She holds a Bachelor of Science degree in Environmental Horticulture and a Master of Science degree in Agricultural Education and Communication from the University of Florida, as well as, several industry certifications including International Society of Arboriculture Arborist, Associate Certified Entomologist, and Florida Nursery Growers and Landscape Association Landscape Contractor. Her background is in the nursery industry, of which she was employed for twenty-two years before joining Extension over eighteen years ago.
Sheila’s programs for Green Industry professionals include Best Management Practices; pesticide applicator certification; and environmentally friendly landscaping design, installation and maintenance. In addition, she provides programming in natural resource stewardship through the Florida Master Naturalist Program.
Born in rural Wisconsin, she spent her early childhood as the son and hunting dog that her father never had, going on hunting, trapping and forest adventures. After moving to Brevard County, FL in 1976, Sheila’s interests turned to cultivating plants and rehabilitating local wildlife by working at a local 40-acre wholesale nursery and tending to the many wounded animals that roamed her parents’ home. She never knew what kind of creature she might find in her bed.
Married to an Air Force mechanic, Sheila spent 14 years traveling the world as a military wife, having two children along the way. Playing softball was a family activity, practicing or competing daily for over 22 years. Sheila was the catcher on the Icelandic NATO Forces Woman’s softball team, the European champions from 1986 -1989. She worked in a large greenhouse and florist while overseas, enabling here to learn even more plant material and utilize those Latin night school classes.
Sheila’s vast knowledge of Florida’s natural resources and cultivated plants was sparked early in life and has continued to grow as she settled into Northwest Florida, working at local retail nurseries and completing her education. Working closely with landscapers, pest control operators and government parks crew to keep up-to-date on plant maintenance, water protection and integrated pest management have become her main daily focus. But, she still finds time to introduce her grandchildren to the wonders of nature.
American Beautyberry Photo by: UF/IFAS
Each fall, nature puts on a brilliant show of color throughout the United States. As the temperatures drop, autumn encourages the “leaf peepers” to hit the road in search of the red-, yellow- and orange-colored leaves of the northern deciduous trees. In Northwest Florida the color of autumn isn’t just from trees. The reds, purples, yellow and white blooms and berries that appear on many native plants add spectacular color to the landscape. American Beautyberry, Callicarpa americana, is loaded with royal-colored fruit that will persist all winter long. Whispy pinkish-cream colored seedheads look like mist atop Purple Lovegrass, Eragrostis spectabilis and Muhlygrass, Muhlenbergia capillaris. The Monarchs and other butterfly species flock to the creamy white “fluff” that covers Saltbrush, Baccharis halimifolia. But, yellow is by far the dominant fall flower color. With all the Goldenrod, Solidago spp., Narrowleaf Sunflower, Helianthus angustifolius and Tickseed, Coreopsis spp., the roadsides are golden. When driving the roads it’s nearly impossible to not see the bright yellows in the ditches and along the wood’s edge. Golden Asters (Chrysopsis spp.), Tickseeds (Coreopsis spp.), Silkgrasses (Pityopsis spp.), Sunflowers (Helianthus spp.) and Goldenrods (Solidago spp.) are displaying their petals of gold at every turn. These wildflowers are all members of the Aster family, one of the largest plant families in the world. For most, envisioning an Aster means a flower that looks like a daisy. While many are daisy-like in structure, others lack the petals and appear more like cascading sprays.
So if you are one of the many “hitting the road in search of fall color”, head to open areas. For wildflowers, that means rural locations with limited homes and businesses. Forested areas and non-grazed pastures typically have showy displays, especially when a spring burn was performed earlier in the year. Peeking out from the woods edge are the small red trumpet-shaped blooms of Red Basil, Calamintha coccinea and tall purple spikes of Gayfeather, Liatris spp. Visit the Florida Wildflower Foundation website, www.flawildflowers.org/bloom.php, to see both what’s in bloom and the locations of the state’s prime viewing areas. These are all native wildflowers that can be obtained through seed companies. Many are also available as potted plants at the local nurseries. Read the name carefully though. There are cultivated varieties that may appear or perform differently than those that naturally occur in Northwest Florida. For more information on Common Native Wildflowers of North Florida go to http://edis.ifas.ufl.edu/ep061.