Trees, Shrubs and Perennial Flowers

a. Working With Our Soil Type:

• Most of our local soils are high in clay content. Unfortunately, this reduces the water infiltration rate and increases waste water runoff. Water slowly, deeply and less frequently. Frequent and light watering results in shallow root systems, making plants less drought-tolerant.
• Incorporate organic matter into your soil to increase water absorption, ease root growth and achieve healthy levels of soil moisture retention. Check with your local landscape professional for recommended organic materials and incorporation rates.

b. Planting With Purpose:

• Choose plants that are appropriate for the specific location in which they are to be placed, (wet, dry, sunny, shady). Follow USDA planting zone recommendations.
• Use landscape plants with greater drought tolerance and disease resistance.
• Mulch large areas around landscape plantings to keep turfgrass away from feeder roots.

a. To Water or Not to Water?

• To check, pull mulch back from around the center of a plant and pick up a small amount of the soil. Squeeze the soil in your hand, and attempt to make a ball. If the soil is sticky and muddy, the plant has excess moisture. If the soil stays in a ball but is not sticky, the moisture is sufficient. If the soil does not stay together, the soil is dry, and moisture should be applied. If your soil has not been modified with organic amendments and is high in clay content, the soil ball may not break apart when dry.
• Most plants in our clay soils fail due to over-watering. Landscape plants need about one inch of moisture per week.
• Check plants on a consistent basis. Test at least every seven to ten days if we are experiencing drought conditions. Smaller shrubs and perennial flowers with smaller root balls often dry out faster than the surrounding soil and these may require more frequent checks.

b. Recognizing Drought Stress

• Drought can impose visible stress on plants quickly, or the damage may take years to appear.
• Deciduous leaves may develop brown edges or browning between the veins. They may also grow smaller than their normal size. Premature leaf drop is common.
• Evergreen leaves and needles may turn colors such as yellow, red, purple and brown.

c. New vs. Established Plantings

• Most established plantings have well developed root systems, which allow them to find and utilize moisture more efficiently than newer ones.
• New plantings possess a limited root system and require more monitoring during the first few years. They are easily drowned by too much moisture and show drought stress quickly.

d. Winter Watering

• Winter watering during drought conditions can be an advantage for many plants, especially those with evergreen foliage. Water them when temperatures reach 40 degrees and above.

Whatever method you choose, keep in mind the following:

• Apply moisture slowly and deeply. Remember, our heavy clay soils will only accept so much water at a time.
• All watering recommendations should be adjusted in relation to the current weather conditions. If you have an automatic irrigation system, DO NOT let the automatic timer be your only guide. For example, reduce water applications to compensate for sufficient rainfall already received.
• Water primarily near the center of a plant.
• Avoid using watering methods that spray water up into the air. Much of the water is lost to evaporation. Low trajectory watering pattern sprinklers, open hose ends, or drip systems are the most efficient.
• Periodically inspect your watering system for needed repairs. Fix leaks and poorly adjusted sprinkler heads. Avoid wasting water on concrete surfaces and streets.
• Avoid moisture on landscape plant foliage. This promotes disease and stress. Watering early in the morning will allow foliage moisture to dry off before the heat of day and reduce evaporation loss. If you must water later in the day, do so early in the evening so foliage can dry off before the coolness of evening when fungus and other disease problems can occur.
• Examine the water needs of various areas on your property, and water accordingly. For example, water those areas that are drier more often, and those known to be regularly moist, less often.

Unlike some turfgrasses, our trees, shrubs, and perennial flowers cannot be "weaned" into a dormant state during the growing season. Stress and tissue damage can incur. Here are some practices that will help in drought or any conditions.

a. Balanced Watering Plan

• Fluctuation from excessive to little or no soil moisture causes plant stress. Checking your plants on a consistent basis and applying the appropriate amount of water is best.

Mulch

• Use some type of organic mulch in your planting beds and around newly planted trees. Mulches reduce moisture evaporation, keep the soil surface cooler, protected, and assist in the control of unwanted weeds.
• Apply mulches in a 3- to 4-inch depth.
• Wood mulches are commonly used and can improve our clay soil over time as they decompose. Do not place wood mulch directly against the plant trunk.

Keep Plantings Healthy and Weed Free

• A vigorous, healthy plant is more likely to endure periods of stress such as drought and be less susceptible to disease.
• Weeds compete for moisture, nutrients, root space and light, so it is important to keep weed growth under control.
• Fertilize plants at proper times, primarily spring and late fall. Do not fertilize plants under drought stress. This may burn root systems or stimulate new top growth, which the plant cannot maintain during times of limited moisture.