Watering Tips For Drought Conditions

We frequently experience hot, dry conditions during the summer months in good ol' Oklahoma.  When drought conditions are prolonged, landscape plants, trees and lawns may suffer temporary or permanent damage.  Hopefully, this will help you make the right decisions for watering and managing your landscape when Mother Nature decides to turn the spigot off.

Plants are like water pumps, drawing in moisture from the soil that is used for plant growth and then releasing water from stems and leaves through a process called transpiration.  Plants begin to wilt and suffer drought stress when the transpiration rate exceeds water uptake.  Drought periods that occur during the long-day months of June, July and August are more damaging than those in September because of increased day length.  Dry breezes also contribute significantly to drought stress.

Signs of drought stress:

In addition to wilting, plants will exhibit some or all of the following symptoms during a prolonged drought:

• Upward curling or rolling of leaves

• Yellowing and browning of leaves, particularly along leaf margins and tips

• Under-sized and off-flavored fruits, vegetables and nuts

• Under-sized leaves; twig and branch dieback

• Blossom and fruit drop

• Interior needle and leaf drop on conifers and evergreens

• Iron chlorosis symptoms on foliage (leaf yellowing between veins)

Secondary problems associated with drought:

• Spider mite infestations

• Blossom-end rot of tomatoes, peppers, squash and melons

• Increased wildlife feeding on fruits and vegetables

• Increased damage by insects driven into home landscapes by a lack of food and water

Long-term consequences of drought:

• Increased susceptibility to attack by insect borers

• Increased susceptibility to certain plant diseases

• Root death

• Diminished winter hardiness

• Terminal dieback; dead twigs and branches

• Eventual plant death

Prioritize Your Plants:

First, determine which plants are most susceptible to water stress.  High on your watering list should be plants that are valuable in terms of replacement cost, prominence in the landscape and enjoyment.  Below is a rating system for prioritizing the water needs of typical landscape plants:

High Priority

Trees and shrubs that are young and planted in an exposed site are very high priority.  Large, mature shade trees and shrubs can be left alone unless the drought is severe and the trees begin to wilt, or the root systems have been recently disturbed.

Medium to High Priority

Perennials, fruit & nut trees, small fruits & vegetables and turf that is less than one year old. Keep a watchful eye on these and deep irrigate as needed.  We suggest holding off on fertilizing during times of drought.

Low Priority

Lawns composed mostly of turf-type tall fescue will withstand some  drought conditions unless they are newly seeded or sodded.  Fescue will suffer in times of excess heat and drought.  Fescue lawns will turn brown and become dormant during times of drought and green back up once cooler weather returns.   Bermuda and zoysia are warm season grasses that cope well with hot, dry weather and require little irrigation once established.  Increasing your mowing height to 2.5 to 3" for cool-season grasses will also help.

Cultural Tips:

• Mulch around plants to conserve soil moisture and keep weeds to a minimum. 

• Avoid using fertilizers or pesticides.  Fertilizers can damage already stressed root systems and pesticides may burn plant foliage.

• Resist the temptation to prune 'dead wood' from your woody ornamentals.  Wood that is obviously dead may be removed at any time.  However, drought-stressed plants can become dormant and may appear dead.  Keep this in mind:  dead wood is brittle and brown under the bark, while dormant wood is green under the bark.

• Keep foot and equipment traffic to a minimum on dormant turf.  Turfgrass can become brittle during a drought and are more easily damaged by compaction.

• Keep turf at least 2 feet from the trunks of young or newly planted trees because it competes with the trees for water.  Apply a mulch in this area.

• Control weeds around shrubs, vegetables and flowers.  Weeds can out-compete cultivated garden plants for water and nutrients.

• Replace declining or dead plants with those that are more drought tolerant and hardy. 

• Leave shallow pans of fresh water out for wildlife and beneficial insects.  Keep birdbaths filled with fresh, clean water. 

• If you need assistance never hesitate to ask our specialists.

• When possible, add organic matter to the soil on your property.  This will improve water-holding capacity during dry weather and promote good drainage during wet weather. 

Watering Tips: When

• Water when the soil is dry.  Soil that cannot be formed into a ball is too dry to supply water to plant roots.

• Water when plants first begin to wilt.  the needles of evergreen shrubs and trees will become dull-colored when water-stressed.  Leaf browning is a sign that drought damage has already occurred.

• Water in early morning, if possible.  Evening watering is fine, although it may contribute to disease problems.

Watering Tips:  How Much

• A good rule of thumb is to apply 1 gallon of water per square foot of root zone once a week.  This will depend of course on the type of plant and its growth stage. Seem complicated?  Just remember to check your plants often during drought.  Dig under the mulch and actually feel the soil.  If it feels dry, you better water.

• Sandy soils need to be watered more often than soils high in clay.

• Water will penetrate grass and mulch covered soils more quickly than bare soils.  Bare soils high in clay often form a crust that limits water infiltration.

• Pull back your mulch to be sure the water is getting past it to the root zone.  Check the soil wetting depth with a stake or even a pencil.  To adequately wet the root system you need to thoroughly moisten the top 4-6 inches of soil.

Application Methods: 

• It is very important to apply enough water to thoroughly wet the root zone.  The larger the plant the larger the root zone.  The root zones of trees and shrubs extend out from the trunk in an area at least equal to the height of the plant.

• Water plants slowly and deeply.  How often depends on your soil type, the type of plant you have and other environmental factors.  Plants like to have a slow watering so they water actually percolates down through the soil to the root zone.

• Invest in soaker hoses or a drip irrigation system.  These operate at low pressure and deliver water slowly and efficiently to the root zone.

• Water sprinklers should be moved back and forth to prevent soil erosion and run-off onto driveways and sidewalks.