University of Illinois Extension
Bruce Spangeberg

These articles are written to apply to the northeastern corner of Illinois. Problems and timing may not apply outside of this area.

Stateline Yard & Garden

Landscape Plantings and Drought Stress

August 6, 1998

Heavy rains over much of the area in June are now a distant memory. Browning lawns and wilting plants are now the common sight on area landscapes, making watering necessary. Set priorities when deciding what yard and garden plants to water.

For example, vegetable crops may be in a critical stage for drought stress. Adequate water is needed to fill out the ear of sweet corn, pod of beans, and developing tomatoes and peppers. If plants are under drought stress, harvest yields and quality will suffer. Gardens that have been mulched will thrive longer without rainfall or irrigation. Try to water early in the day and do not work among wet plants if at all possible to help reduce disease potential.

With trees and shrubs, first priority for watering should be new plantings, such as from earlier this season. Established trees and shrubs also need water, especially if conditions remain dry. Water the entire rootzone area. Be careful, however, not to overwater, especially on clay soils. There have been instances where trees or shrubs have died due roots dying from sitting in excessively wet soil even though the weather has been dry.

Lawns may be the most visible area of the landscape showing drought stress, yet in reality may be able to tolerate drought very well. Cool-season grasses go dormant and resume active growth when conditions improve. The common question is how much water is enough to keep the turf alive. Applying 1/4 to 1/2 inch every 2 to 4 weeks should be enough to maintain moisture in stems and roots so lawns survive and resume growing when conditions improve.

Flower beds and groundcover plantings also need watering. Frequency and amounts will vary according to the species present and site conditions. For example, perennial beds with species more tolerant of dry soils, such as yarrow, purple coneflower, Liatris, or sedum can usually get by with minimum need for watering. Other species may need frequent irrigation to remain healthy. Careful planning can make maintenance practices, such as watering, much easier.

Hopefully some timely rains will come in early August to help relieve drought stress on plants. In the meantime, evaluate your landscape plantings and put together some watering plans to assure plants make it through the dry weather.


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