One of the most frequent causes of harm to landscape plant material is improper applications of water, either too much or too little. Applying supplemental water properly and at the right time is important in keeping the plants healthy. Many established ornamental plants can go extended periods without water. Even during droughts, more plants die from overwatering than lack of it.
For example, junipers can tolerate prolonged dry spells, but they will perish if over watered or if planted in poorly drained soil.
At the first signs of moisture stress, plants should receive supplemental water. Symptoms include wilting and the development of a pale gray to green coloration. Lawn areas need water if you can walk across the grass, and your foot prints are visible. To determine if water is needed, use a small shovel to dig a few inches near the root zone. An application of water is needed if the soil feels dry and powdery. Well watered soil will stick together when it is pressed into a ball. The soil should be kept evenly moist, not too dry or too wet.
Often the water only wets the upper couple of inches of the soil and does not penetrate deeply into the root zone. This results from applying only enough water to wet the upper layers of the soil. The plant’s susceptibility to environmental stresses, insect and disease problems is increased since the roots are weak and shallow. Water thoroughly and long enough to allow it to penetrate deeply into the soil to encourage the development of a deep extensive root system. Use organic mulches, such as pine straw or pine bark, on the surface of the soil to reduce the loss of water through evaporation.
Make sure the water is reaching the intended plant material. Much of the water applied to landscapes is not absorbed by plants and is lost by evaporation or runoff. On lawns, adjust the sprinklers so they are irrigating the grass, not the pavement. Lawns require roughly one inch of water per week. Place a rain gauge outside to measure the amount of water that the sprinklers are emitting. For trees and shrubs, apply water slowly by hand or use a soaker hose instead of sprinklers to direct the water to the base of the plant. Irrigate before noon in order to reduce the water that is lost through evaporation during the heat of the day. This will also allow the leaves to dry out before nightfall, which will prevent the development of diseases.
Remember, adequate water is essential to maintaining a healthy landscape. Apply the correct amounts at the right time will go a long way in keeping your plants attractive and in good shape. Timothy Daly, MS, Agricultural and Natural Resource Extension Agent, Gwinnett County Extension. Tim may be contacted by phone at 678-377-4010 or by email at email@example.com