Watering

Symptoms of Drought-Stressed Trees

How can you tell if your tree or shrub needs water? Conditions are get dry enough in Northwest Arkansas that most trees would greatly benefit from supplemental water. Though drought symptom evidence may not show immediately, the following conditions are clear signs that a tree needs water:

• Deciduous leaves droop or wilt
• Deciduous leaves curl. Leaves curl down to reduce airflow on the underside of the leaf and to decrease sun exposure on the top of the leaf
• Deciduous leaves turn yellow; veins or outside edges turn brown
• Evergreen needles turn yellow

What are some tips on watering and saving water? Focus on watering underneath the canopy of deciduous trees. Allow the hose to distribute water to different areas under the canopy. Conversely, evergreen trees should be watered up to five feet beyond the drip line of the canopy. Allow the hose to apply water around the entire circumference of the evergreen tree.

Focus on watering only the soil under or near the trees and ensure that water is not wasted on sidewalks, driveways, or the leaves of trees. Although little rain has fallen here recently, times of dry weather are perfect opportunities to remember the value of this resource and consider collecting rainwater from future precipitation. Simple collection from the roof via gutters or piping and a barrel can reduce the amount of freshwater needed to pump from the freshwater hose.

Watering Techniques and Suggestions

The following are suggestions on efficient and effective tree watering:

• The best time to water is at night or early morning from 10 p.m. to 8 a.m. Trees relieve water deficits (refill) over the night-time hours. Watering at night allows effective use of applied water and less evaporative loss.
• Saturate the soil around the tree within the drip line (the outer edges of the tree’s branches) to disperse water down toward the roots.
• Water three to five above the drip line on all sides of the tree for evergreen trees and shrubs.
• A few heavy (high volume) waterings are much better than many light, shallow waterings. The objective is to water slowly, dispersing the water flow to get the water deep down to the tree’s roots.
• Avoid digging holes in the ground to water deeply. The holes will dry out the roots even more. Overhead spraying of tree leaves is inefficient and can cause the tree to lose water in the leaves. Overhead spraying should be avoided during drought conditions. Water should be released from the hose close to ground level.
• Trees in limited rooting areas, such as in containers or pots, on major slopes or confined by pavement or driveways, will need additional care to ensure water reaches the root system in adequate amounts.
• Do not fertilize during a drought. Trees rarely need fertilization. 
• Treat pests or diseases quickly. Drought stresses a tree or shrub and makes it vulnerable to pests and diseases. These factors further stress the tree and cause a downward decline in the plant.