Cold conditions can damage plants and features in the landscape; however, risks can be reduced through employing a variety of practices before, during and after winter weather occurs. Louisiana winters are anything but predictable, as recently demonstrated by the historic snowfall covering south Louisiana in January 2025; however, a few freezing spells are more commonly expected winter conditions in Louisiana. Variability between different regions of Louisiana is important to remember when it comes to both winter maintenance and plant selection. The 2023 USDA Plant Hardiness Zone Map (Image 1) reflects the average annual lowest temperature over a span of time (in this edition, 1991-2020), where different regions of Louisiana would be considered relatively colder (i.e. Shreveport, zone 8b) or warmer (New Orleans, 9b or greater). Heat retention associated with urban areas can create warmer microclimates within an area, with parts of New Orleans reaching zone 10. While winter preparation plans may vary between regions of the state, the following practices can help protect your plants and prevent problems.

Image 1. 2023 USDA Hardiness Map for Louisiana. Map by U.S. Department of Agriculture and Oregon State University

Before Winter Weather Events

Expectations and inventory: Knowing your zone is important when selecting plants. Certain plants may perform as perennials in south Louisiana, surviving the milder winters observed in the region, but may be better utilized as annuals in north Louisiana. Take inventory of your plants with each cold weather event. The first frost of the season often leaves the most visual of damage in the garden (marking the end for many summer annuals), but cold weather events later throughout the winter season can continue to cause problems, especially if temperatures plunge. Plants that survive an initial, mild frost may indeed be damaged by later, colder weather events, so taking stock of plant health before and after each cold weather event can help understand your landscapes tolerance for cold conditions.

Mulching: Spreading a layer of mulch (typically 2 to 4 inches) over landscape beds helps to insulate soils from rapid temperature shifts and evaporative water loss. LSU AgCenter research indicates that even just 2 inches of an organic material such as pine straw can effectively buffer temperatures. Beds without mulch are more prone to rapid heating or cooling when compared to beds with mulch. Considering that Louisiana winters may commonly have a particularly cold day followed by a sudden shift to warm weather, using mulch to mitigate temperature fluctuations (in either direction) is a simple step to protect your landscape.

Irrigation: When cold weather is on the horizon, irrigating landscape beds before temperatures drop is a great way to offer insulation to plant roots. Water has a greater specific heat than dry soil, which effectively means that a hydrated soil has greater temperature buffering capacity than a dry soil. The water within soils will absorb heat during the day and release it at night, offering more insulation to the plant roots. Apply irrigation before temperatures drop, ideally a day or two or the morning before cold weather occurs. Apply water directly to the soil but avoid oversaturating the root zone. A little bit of hydration goes a long way, but too much can pose problems, particularly in poorly drained soils.

Covering plants and frost cloths/fabrics: Covering sensitive plants can be an effective practice for winter protection (Image 2). It is important to remember that plants are sensitive to the air temperature and not wind chill, so base your management plans on actual air temperature. Wind chill recognizes the removal of heat from a boundary layer, such as the air just outside of our skin. Plants do not generate heat like humans do, so these effects are not felt by the plant That said, cold winds can still cause desiccation and damage to plants, but this differs from actual freeze damage. Providing coverage to plants in cold weather can raise temperatures by a few degrees, which may be the difference between fleeting frost damage and a freeze-induced farewell to your plants. Simple covers like blankets, cardboard boxes or other materials that you have handy at home can help; however, materials engineered for winter plant protection are specifically designed for the task. Frost cloths and fabrics are available in different forms (such as woven or nonwoven materials) and weights, offering varying levels of temperature insulation, light transmission and appearance in the landscape. When placing any type of cover on plants, make sure it is draped over the plant and touches the ground. This traps the heat radiating from the soil. It is important to monitor weather patterns and be prepared to put on or take off covers as needed. Sudden shifts to warm weather can cause covered plants to heat up too much, so be mindful about leaving cover on too long. In practice, covering plants in late afternoon can retain some of the daytime heat throughout the night, and removing cover the next day — especially if temperatures suddenly shift upward — can keep temperatures from climbing too high. Remember, many plants do not take kindly to sudden, drastic shifts in temperature, so minimizing extreme shifts should be the primary goal. Covering plants may help maintain aesthetics, as demonstrated by the covered Farfugium looking more appealing after a frost than its uncovered counterparts in the background (Image 3).

Doing nothing: Counterintuitive as it may seem, some of the best winter protection practices involve doing absolutely nothing in some cases and for certain plants. Leaf litter provides a home for beneficial insects to overwinter (Image 4). Removing fallen leaves not only removes this habitat but removes the above-stated benefits of this natural mulch. Similarly, ornamental grasses provide a valuable cover for critters in the landscape. Ornamental grasses should be pruned at the end of winter or early spring to support new growth, but premature pruning, especially in the heart of winter, removes this valuable habitat for wildlife. Not to mention, letting the faded foliage of ornamental grasses remain through the colder months offers insulation to the plant and adds interest to the landscape. Ideally, cut back ornamental grasses in early March. Cutting ornamental grasses too early removes wildlife habitat, detracts from aesthetics, and may change how people perceive and interact with the site (Image 5).

Frozen features: Frozen water expands, and water trapped in various features can cause damage to sensitive objects in the landscape. Irrigation parts (sprinklers, valves, etc.), water features (fountains) and sensitive electrical components may be damaged if left in cold conditions. Just like plants, wrapping these features with some sort of cover can provide a little insulation that can go a long way. Draining water from sensitive features or disconnecting certain parts until spring can be a good practice. For example, a battery-operated timer, lawn sprinkler and hose can be disconnected, drained and stored until it is ready for reuse, rather than risk damage during freezing events.

Container considerations: There are challenges and opportunities with container plants during cold weather. Roots that would otherwise be insulated by surrounding soils in the landscape have less protection when kept in an aboveground container. Fortunately, container plantings can be moved, although you may need a machine, depending on container size, rather than muscle. Bringing containers into a sheltered location such as a garage or to somewhere with more protection may be wise. Consider placing them alongside a house to be closer to ambient heat or away from windy areas.