Freeze warning is a terrifying phrase for gardeners. Cold damages your plants and may even kill them outright. Understanding how plants freeze will help you create mitigating strategies for their preservation. Informing yourself as to how freeze damages plant tissues will allow you to fortify your garden.
How do Plants lose Heat
Cold exposure happens in a couple of ways. Radiant heat loss occurs when one surface emits waves of heat into a colder surrounding environment. The surfaces of leaves and stems are not immune to this type of temperature transfer, nor is the soil in your garden beds. Frost may or may not form depending on moisture levels in the air, but cold damage will still be the result. The other main source of heat loss in gardens is through Advective freezes. These occur when cold air from the north moves south en masse resulting in colder temperatures and often increased winds. Mitigating this is a little tougher than radiant losses but not impossible
IFAS Photo
As with all things, planning is at the forefront. When designing your garden, cold hardiness should be considered. Certain plants naturally handle cold weather better than others. Utilizing native plants and those specified for your USDA hardiness zone will keep gardens alive in winter months. These tend to be acclimated for colder temperatures. Once the proper plants are selected and planted, ensure they are properly treated. Keeping your plants as healthy as possible is also critical in cold tolerance. Mulches and watering prior to a freeze event will reduce risk from radiant heat loss. The water absorbs warmth through the day and holds onto it more efficiently than dry soil would. Addition of a frost blanket will further reduce heat lost and ultimately the damage to your plants. A slightly more in-depth protection method comes from establishing microclimates in your yard. Use taller trees and windbreaks. Taller trees create a canopy that blocks heat loss to the atmosphere. Windbreaks keep the colder air away from your gardens and again prevent heat loss. None of these methods are fool proof but will help keep your gardens alive through the colder months. You may still experience damage from freezes. If this does happen, make sure your plants are watered to thaw any roots ensuring they function properly. Inspect stems by scraping a little tissue. Prune away any that shows black or brown tissue while keeping any which still looks green.
IFAS Photo
Summing up
Freezes can be devastating to your gardens. A little knowledge can go a long way toward mitigating loss. For more information on cold protection, see this Ask IFAS document, or contact your local extension agent for additional information on this and any topic regarding your gardens and more.
Have you ever visited a public garden or a park and wondered what type of plant you were looking at? Or found the name on a sign but wondered – can I grow that at my house? How big will it get? Does it have flowers, berries, keep its leaves in the winter? We feel your pain, fellow plant lovers!
Gardens are ever evolving and providing up to date printed information on all the plants can become difficult to manage and involve a lot of wasted resources. In Bay County, we have several gardens at the Extension Office, and we try to keep everything labeled, but space on signs is limited to plant name and we want to teach gardeners how to grow not just identify plants. To expand outreach of Florida-Friendly plants, we have created a website with all the plants in our demonstration gardens.
The site is organized by garden area, common name, and botanical name to ease navigation. Each plant profile has photos at different stages, basic cultural information, and links to additional research-based information.
Whether you are visiting our gardens in person or just want information on plants that perform well in the Florida Panhandle, we hope you will check out our new site and let us know if you found it useful and how we can improve.
Pollinator hotel. J. McConnell, UFIFASGinkgo leaves. J. McConnell, UFIFASBlanket flower. J. McConnell, UFIFASAmerican beautyberry. J. McConnell, UFIFASEastern redbud. J. McConnell, UFIFASPollinator garden. J. McConnell, UFIFASMaypop flower. J. McConnell, UFIFASAutumn fern. J. McConnell, UFIFASHummingbird at red bottlebrush flower. J. McConnell, UFIFAS
October is an important month for butterflies. The monarchs are making their epic migration towards Mexico, gracing us with their presence as they stop to feed on saltbush or lantana plants along the coast. But our homegrown orange-and-black butterfly is showing up everywhere right now, too. The Gulf fritillary (Agrautis vanillae) is a smaller species, but also features bright orange wings with black stripes and spots. Their caterpillars come dressed for Halloween, too—they are a deep orange color with black legs and spikes. While the caterpillar is not venomous to any potential predators, the spikes are quite intimidating and serve a protective function.
A gulf fritillary butterfly gathering nectar from a similarly brilliant orange flower. Photo credit: Carrie Stevenson, UF IFAS Extension
Fritillary (name from the Latin “chessboard”) eggs are bright yellow and laid primarily on varieties of passionflower vines, which the caterpillars feed voraciously upon. Passion vine is an important host plant for the zebra longwing as well, which is Florida’s state butterfly.
Gulf fritillaries are found in all 67 Florida counties, and may live throughout the southeastern United States, Mexico, and central and south America. They are found in varied habitats but prefer open, sunny spots in fields, forests, and gardens. The butterfly’s wing shape puts them into the “longwing” category, as their elongated wings spread wider than other species.
Caterpillar of the Gulf fritillary butterfly on corkystem passionflower. Photo credit: Jaret C. Daniels, University of Florida.
In the fall, fritillaries migrate to the warmest ends of their range. By spring, they move slightly north into North Carolina or interior Alabama.
Credit: Jeff McMillian, hosted by the USDA-NRCS PLANTS Database. Illustration credit: Mary Vaux Walcott, North American Wild Flowers, vol. 3 (1925)
Yaupon hollies, Ilex spp., are a native plant to Florida that grow very well and abundantly in our local soils. The yaupon holly is one of the hardiest holly species found in Florida. You may see this holly grown as a tree, large or small specimen shrub, or even as a hedge. Using a low-input native plant like yaupon in the landscape can result in less nutrient pollution, reduced water use and resilience through drought, freezes, and hurricanes. This plant thrives in the southeast and is hardy up to USDA zone 7. They can even tolerate temperatures as low as 10F for short periods of time. Pollinators are also attracted to the yaupon flowers – if you are trying to attract bees for other crops on the farm, this is the plant for you! Growing yaupon is much easier than other crops because the species can handle a variety of conditions, from full sun to light shade and soil from dry to wet. Growth rate is moderate when they are young and slows as plants age. Yaupon hollies are good for stabilizing the soil, preventing erosion, and providing a habitat for wildlife.
Yaupon is a very old plant that historically has been used as an important food source, medicine and even a ceremonial item by Timucua Indigenous groups for thousands of years. The Timucua people of Florida believed that yaupon purified the mind and body of those who drank it. Yaupon is the only naturally caffeinated plant species grown in the United States. It provides a balanced caffeine boost without the bitter tannins that you get from regular tea. Yaupon contains 30% less caffeine than coffee but provides a dose of theophylline and theobromine. These 2 compounds provide an energy that will not cause jitteriness and caffeine crash that other caffeinated beverages can give you. There are also dozens of vitamins, minerals, amino acids, polyphenols and antioxidants to protect the body, and these can help calm the mind as well.
‘Schilling’s Dwarf’ is a yaupon cultivar perfect for homemade tea production. The plant gets no taller than four feet and four feet wide. While you can make yaupon tea from any yaupon holly cultivar, all ‘Schilling’s Dwarf’ clones are also all male, which means no berries will get in your way of harvesting leaves. To prepare tea from the yaupon plant, leaves are removed from the stems and lightly washed, discarding any berries and debris. The stems may also be used and will not change the flavor. Next you will dehydrate leaves and stems by air or sun drying. Leaves can be stored whole or crushed and blended into smaller pieces if desired. These leaves produce a caffeinated beverage that is similar to green tea with grassy flavors. If these same leaves are lightly roasted, over a hot pan or in the oven, it will produce an earthier beverage that can have notes of malt and toasted coffee.
Homeowners are able to select Thryallis as a low maintenance shrub for the North Florida landscape. Learn the characteristics of this Florida Friendly plant with UF IFAS Extension Escambia County!
