Protect your landscape during times of drought

Weather Impacts – Heat Wave, Drought and Dry Weather

David Zlesak, Regional Extension Educator in Horticulture

Yellowing older foliage and yellowing or browning leaf edges of newer leaves are tell tale signs that this rhubarb plant is suffering from drought.

Hydrangea plants are particularly sensitive to drought and commonly display symptoms including wilt and dying older foliage.

Photos by David Zlesak

Drought stress from above average May and June temperatures and lower than normal rainfall is beginning to take its toll on plants in Twin Cities landscapes. Lawns, trees, shrubs, perennials, and annuals alike suffer from drought and express symptoms including reduced growth, yellowing, wilt, loss of branches and leaves, or in severe cases whole plant death. Recent plantings and containerized plants are particularly sensitive to drought due to limited root systems from which to draw water from the soil. Irrigating when rainfall is insufficient and using techniques that conserve soil moisture and reduce water loss will help protect your landscape through this critical time.

Here are some tips to help plants through times of drought:

The Inch Per Week rule. If there is not an inch of rainfall per week, provide the difference through irrigation. Even more than one inch per week may be needed to keep your landscape plants thriving depending on weather and your site.
Mulch conserves soil moisture by reducing evaporation. A blanket of mulch shades the soil and reduces soil temperature which helps to conserve soil moisture. Consider using organic mulches (bark, wood chips, leaves, cocoa bean hulls) that once decayed, benefit the soil in comparison to rocks. Apply a fresh layer of mulch to areas where it is thin and soil is becoming exposed.
Water deeply and less frequently rather than shallowly and more often. Soaking the soil deeply every couple or few days rather than light waterings daily will help encourage roots to grow deeper and plants to be more drought resistant.
Water in the morning. Cooler temperatures, reduced wind, and higher humidity in the morning help more water soak into the soil rather than be lost from evaporation. Morning sun and rising temperatures also help promote foliage to dry quickly and reduce the risk of foliar diseases compared to evening waterings. When plants are under severe drought stress watering as soon as possible minimizes further damage, regardless of the time of day.
Consider time saving methods to help get the job done . Soaker hoses and sprinklers strategically placed in the landscape with snap on connection valves can be used alone or combined with programmable automatic timers connected to your water faucet.
Choose to use drought-resistant plant materials . Consider native and other plant materials which have greater drought resistance. Check the following website for a list of drought-resistant plants: http://www.sustland.umn.edu/design/drought.htm
Direct limited resources to plants most in need of water. When time and water resources are limited, one can direct watering efforts to plants with greater drought sensitivity and try to locate such plants closer to the water source.

For new plantings and containers:

Shallow basins around plants help collect water and allow it to slowly soak in . Making a shallow basin a foot or two wide with a rim of soil an inch or two high helps to channel water around the developing root system.
Newly seeded or sodded lawns need to be watered frequently . Newly planted grass is particularly sensitive to drought due to shallow, unestablished root systems. Water once or preferably two or three times daily during the initial stages.
Repot containerized plants into larger containers . Containerized plants can dry out very fast, especially as they grow in size and their water demands increase. Repotting into larger containers allows for more soil volume and potential to hold more moisture. Consider trying hydrogels (beads or crystals which swell once soaked in water) mixed into potting soil. They are reported to act as a water reserve, slowly releasing water to plants as needed.

Keeping your landscape plants healthy through this time of drought will help protect their appearance and health now and prepare them to better survive the upcoming Minnesota winter. For more information about caring for plants in the home landscape visit the University of Minnesota Extension Service Yard and Garden Line website.

URL: http:// www.extension.umn.edu/administrative/disasterresponse/components/wi_drought_landscapes.html This page was updated June 21, 2007 .
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