Surviving drought

Preserving a landscape during a severe drought can be one of the most challenging crises in the landscape industry.

Implementing a comprehensive strategy to restore the balance of the landscape is vital to the soil and the industry.

Preparation: It starts with soil.

The soil is the lifeblood of the landscape. Soil, when properly maintained, encourages deep roots. During a drought, plant roots – the storehouse of carbohydrates – are the survival mechanism of the plant.

Preparation for a drought starts with good cultural practices in the soil. Good soil aeration combined with proper fertilization encourages deep rooting. Plants will have greater success in withstanding the devastating effects of a drought if their root system has been cultivated to grow a deeper, extensive root system.

Good soil preparation is not reserved for new landscape installations. Soil cultural practices, such as aeration, can be performed at any time. Spring is the best time because, for most plant material, spring is when a plant’s root development is most active.

Soil fertility and salinity, or the amount of salt found in the soil, are important. In the spring, get a soil sample and have it tested at a soil lab. Once results have been analyzed, correcting any nutrient deficiency is the first step.

For turfgrass, spring aeration is essential to encourage deep rooted turf. Ideally, turfgrass should have rooting depths of 6-12 inches. For trees and shrubs, drilling several holes 2-4 inches in diameter, 24-to 36-inches deep around the base of the plant will encourage deeper water penetration and deeper rooting.

Mow turfgrass higher and be careful about applying too much nitrogen fertilizer. Nitrogen encourages top-growth of grasses at the expense of developing a strong root system.

Deep, infrequent irrigation cycles also encourage deeper rooting. Mulch properly placed around trees and shrubs also helps to preserve soil moisture.

Wilt: It involves water management.

When a drought happens, it is important to have priorities. Trees come first. The loss of shade from a tree increases water evaporation in the surrounding area.

After establishing a healthy root system, pay close attention to the leaves of all plants. The leaves are the best indicator of a plant’s water needs. When turfgrass starts to turn bluish-green, it is time to add water. The wilt symptoms of many trees and shrubs will exhibit leaf folding. Sometimes the leaf folding will also display a slight change in color.
Important steps to take – or not take – during a drought include:

Do not fertilize during a drought. All fertilizers contain salts that will rob the plants of any moisture in the soil. Avoid fertilizing the plants until they have recovered. Fertilizing after a severe drought will usually increase leaf and stem growth at the expense of root development.

Do not prune during or immediately following a drought.

Apply water slowly and deeply to the soil. Reduce evaporative water losses by watering after the sun goes down.

Most importantly, physically check the moisture level of the soil. The soil may look dry on the surface; however, with a soil probe or a 6-inch screwdriver stuck into the ground, you can accurately determine how deep and how dry the soil may be. 

Recovery: Water, water and water.

Recovering trees, shrubs and turfgrass after an extended drought is different for each type of plant. Water, water, water is the keyhelp insure a more successful recovery.

Trees requir to successful recovery. However, the proper watering cycle for each type of plant is different. Monitoring the soil water level during the process will e deep, infrequent watering. Gently soaking the soil to a depth of 36-48 inches is important. Allow the soil to dry out before watering again. Avoid light frequent waterings that will only penetrate the soil to a depth of a few inches. This will result in shallow roots.

For shrubs, watering to a depth of 18-24 inches is important. Allow the soil to dry out before watering again.Recovering turfgrass is the most demanding watering regimen. Initially, light frequent waterings are important. Monitor the soil moisture level with a probe or a screwdriver. Once the turf has started to recover, a deeper less frequent watering schedule can be resumed.

After severe water stress, all plant types slow in growth because their metabolism has been significantly reduced for survival. The water initially applied will be slowly absorbed by the plant. Water absorption by the plant will be dramatically reduced until the plant starts to become healthy again. Once the plant material starts to regain its health, it will rapidly use water.

Understanding how a plant recovers from severe water stress is vital to recovery. Nutritional and watering needs vary widely from plant to plant and from location to location. Careful soil monitoring is key to returning plants to a healthy balance following a severe drought.

The author is a speaker, consultant and the owner at Green Water Infrastructure.