By Heather Kirk-Ballard | LSU AgCenter Horticulturist
Last summer in Louisiana, we were affected by a heatwave that spread across the southern tier of the U.S. This heatwave was caused by a persistent, strong ridge of high pressure in the upper atmosphere that led to low precipitation. This played a key role in the unforgiving high temperatures we endured in 2023.
According to the National Integrated Drought Information System, recent summers have been 1 to 2 degrees Fahrenheit warmer than in prior years. Climate model projections indicate there is a continued and increasing risk of such heatwaves as the climate warms, especially in dry years. And this summer will be no exception. That means it’s time to get prepared for drought and heat conditions in the garden.
Managing drought stress in your landscape requires efficient water use, proper plant selection and diligent care. You can keep your plants thriving during extended dry periods by keeping in mind some basic do’s and don’ts.
Do monitor soil moisture regularly. Mulch, shade and control weeds. Group plants with similar watering needs.
Don’t use unnecessary herbicides or pesticides. Avoid heavy pruning or fertilizing. Don’t ignore water restrictions or waste water.
Let’s start with watering wisely. The best way to water plants is to do so deeply but less frequently to encourage deep root growth. Be sure to water plants early in the morning or late in the evening to minimize evaporation. Use efficient systems and opt for a soaker hose or drip irrigation to deliver water directly to the root zone.
General watering guidelines include watering bedding plants two times a week in times of drought at a depth of 8 to 12 inches. Shrubs should be watered two times a week at a depth of 12 to 18 inches, and trees need to be watered once a week at a depth of 18 to 24 inches.
How do you know you’ve made it to 8 or 24 inches of depth? Use the screwdriver method by inserting a screwdriver or thin metal rod into the soil. If it penetrates easily, the soil is moist; if not, water until moisture reaches the recommended depths. Use a ruler to measure the depth of the soil left on the metal.
Apply a thick layer of organic mulch (wood chips, straw, compost) to retain soil moisture, suppress weeds and reduce evaporation. Use shade cloth or temporary structures to reduce water loss through evaporation and protect plants from extreme heat. In addition, windbreaks such as hedges, trees and tall grass, wooden fences and garden structures such as pergolas, arbors and trellised vines can prevent further drying from strong winds.
Improve soil quality with organic matter to enhance moisture retention. Healthy soils retain moisture better. You can improve soil quality by adding organic matter to improve the water-holding capacity, helping the soil become like a sponge that retains moisture and makes it available over time.
Some great soil amendments that can improve water retention in your landscape are compost, worm castings and aged manure. When using these amendments, it’s essential to follow recommended application rates.
Keep your landscape and garden free of weeds. Weeds compete with landscape and garden plants for water and nutrients. This will help reduce the drought stress on plants.
Be sure to prioritize your water usage. Focus on your most valuable and vulnerable plants first. Healthy plants stand a better chance of surviving droughts with careful water management. Adapt your schedule to your garden’s needs and let less critical areas go without watering if necessary.
Trees are the longest-living plants in the landscape. They are critical to monitor during and after droughts. If you have trees that suffered damage last summer, assess them carefully now. Remember that hurricane season is rapidly approaching.
Dead trees pose significant dangers, including the risk of falling branches or entire tree collapse, which can lead to property damage, personal injury and even fatalities. The cost of removal can vary widely based on the tree’s size, location and complexity, often ranging from $200 to more than $2,000 per tree.
Hiring a licensed arborist is crucial to ensure safe, efficient removal and to avoid potential liability issues. Certified professionals have the expertise to assess the risks, provide accurate estimates and perform the job safely while adhering to local regulations. Visit the Louisiana Department of Agriculture and Forestry website for a list of licensed and insured arborists.