LSU AgCenter Horticulturist
As we approach the year’s end, take a moment to think about the past gardening season. Louisiana gardeners experienced challenges from late spring freezes to a severe summer drought and scorching heat. In reflecting upon the year, valuable lessons were learned, highlighting the garden's dynamic growth. Gardeners must be adaptable and resilient and continue to learn in the face of a changing climate.
Like many things in life, it’s often the hard lessons that stick with us the most. The drought of this past summer really took a toll on our landscape plants. As droughts could become more prevalent in the years to come, we should consider ways to adapt our landscapes to drought conditions. One drought does not mean we will have one each year. But if we prepare, we won’t get caught with our plants down!
Gardeners have an opportunity to learn about water-wise gardening. You can help conserve water by implementing water-saving techniques such as drip irrigation, mulching and rainwater harvesting to maximize water efficiency in your garden. In addition, when irrigating during drought conditions, watering at the right time also can help conserve water. Typically, watering late in the evening and early morning can prevent the loss of water through evaporation.
Next choose drought-tolerant plants that are well-adapted to arid conditions. This summer, we saw magnolias, pines, azaleas and other woody plants suffer, and many died. By choosing succulents, native plants and other drought-resistant species that can thrive with minimal water, you help minimize the losses in your landscape. You also can help plants by managing the soil to improve soil structure with organic matter that enhances water retention. Well-aerated soil with organic content also can absorb and retain moisture more effectively.
Rising temperatures and prolonged heatwaves can stress plants and challenge traditional gardening practices. Opt for heat-tolerant plants that can handle high temperatures. Select varieties that thrive in our hot and humid subtropical climate with relatively mild winters.
Most gardeners have heard about the USDA Plant Hardiness Zone Map, but there is a lesser-known map that considers the heat tolerance of plants.
The American Horticultural Society's Plant Heat Zone Map complements the USDA resource. While the USDA map focuses on winter cold tolerance, the AHS map provides information about the average number of days each year that a region experiences "heat days," or temperatures above 86 degrees Fahrenheit.
The AHS Plant Heat Zone Map is divided into numerical zones based on the number of heat days. The higher the zone number, the more days in the year with high temperatures, indicating the heat tolerance required for plants to thrive in that specific region. This information is particularly valuable for gardeners in warmer climates such as the Gulf South who need to consider not only winter cold but also summer heat when selecting plants for their gardens.
Gardeners can use both the USDA Plant Hardiness Zone Map and the AHS Plant Heat Zone Map together to make more informed decisions about plant selection based on the specific climatic conditions of their region. These maps collectively provide a comprehensive guide for choosing plants that can withstand both cold and heat stresses in a particular geographic area.
Another practice to adapt to excessive heat is to consider creating shaded areas in your garden using structures, trees, or shade cloths. Additionally, be mindful of microclimates in your garden and plant heat-sensitive species in cooler spots and schedule garden activities such as planting, pruning and harvesting during cooler parts of the day to minimize stress on plants and reduce water loss.
Unpredictable freezes in spring and fall can disrupt the growing season and damage tender plants. This past March we had a late, hard freeze that impacted many plants.
Select plant varieties that are more resistant to late or early freezes. Look for plants with a broader temperature range for optimal growth. Stay informed about local weather forecasts and be prepared to take action when a freeze is predicted.
Watering the soil before a freeze can provide some insulation to plant roots. You can use frost blankets or row covers to protect vulnerable plants during unexpected freezes. These materials can provide an extra layer of insulation and prevent frost damage. Make sure covers go all the way to the ground to trap radiant heat.
As climate change continues to influence weather patterns, gardeners must adapt their practices to ensure successful harvests and the overall health of their gardens. Learning from the challenges of the previous year, such as drought, excessive heat and unexpected freezes, allows for the development of resilient gardening techniques. Remember, the key to successful gardening in a changing climate lies in continuous learning, flexibility and a commitment to sustainable practices.
You can use frost blankets or row covers to protect vulnerable plants during unexpected freezes. Photo by Heather Kirk-Ballard/LSU AgCenter
AHS Plant Heat Zone Map. Map by American Horticultural Society
Choose drought-tolerant plants. Photo by Heather Kirk-Ballard/LSU AgCenter