Trees, the largest and most long-lasting components of any landscape, usually receive the least attention when irrigation systems are designed. In truth, depending on their eventual size, soil types, and seasonal water volumes, trees may require some special attention to ensure their long-term health.
Drip Irrigation and Soil Type
In some cases, normal lawn irrigation systems may be sufficient to keep trees sufficiently hydrated. However, we must remember that the roots of healthy trees are meant to stretch deep into the ground and that water must be continually available to ensure the roots receive what they need.
Soil types play a significant role in determining how a tree should be watered. Naturally, in very sandy soils, water tends to flow straight through. In dense clay soils, water flow rates and emitters that supply water, must be carefully programmed to ensure proper deep watering without losing too much volume to run-off.
Designing Drip Irrigation Systems
Any tree, or group of trees, will benefit from a low-volume or drip irrigation systems. As healthy trees mature, their roots want to grow deeper into the soil. Therefore watering strategies that support root development are naturally different for trees than for lawn or shrub irrigation. Again, soil type and system design play an important role in determining how much water will eventually be absorbed by the roots.
For the first few years, a new tree should be frequently irrigated directly to the root ball and out to the tree’s drip line. This ensures the new tree has sufficient moisture to support healthy growth. The irrigation line can be a ½” drip duct coiled around the top of the root ball with about 12” of spacing. As the tree grows, the diameter of the concentric circles of the irrigation line can be expanded to cover the expanding root zone. Because the roots are intended to grow outward as well as downward, the water should support growth in both directions. Wider coverage for outward root growth, and a slow flow deeper hydration for downward growth is the target.
Heritage Oak Farm, a prominent nursery equipment supplier, recommends a ½” irrigation line programmed to emit more water less frequently to reach the deeper root systems. Increasing total water distribution as trees mature is a good idea.
For more information contact, visit the website, https://www.heritageoakfarm.com/ or call 1.888.208.5308.