Decline or death of trees and shrubs after transplanting is often caused by poor root establishment. New root growth is most important for successful establishment and future growth of plants. A recent study by the University of Arizona’s School of Plant Sciences has found that Rain Bird’s Root Watering Series (RWS) irrigation products help tree and shrub root systems become established more quickly by providing water, oxygen and nutrients at lower levels in the rootzone.

Plant scientist and researcher Dr. Ursula Schuch conducted the study, which examined the growth, establishment and survival of 48 ash trees transplanted at a test site in Tucson, Ariz. Half of the 8-foot-tall trees were each irrigated with a pair of RWS-M 18-inch canisters installed in-ground near the trees’ root ball. The remaining 24 trees were irrigated at ground level with bubblers near the trees’ trunk. All 48 trees received the same amount of water at the same frequency throughout the study. Dr. Schuch and her staff harvested the trees at three, eight and 13 months after transplanting to collect data for the study.

The study found that just three months after transplanting, the trees irrigated with the RWS units had 48 percent more new deep-root growth than the trees watered with surface bubblers, anchoring them more securely and allowing them to tap a larger soil moisture reservoir. The overall root mass of the RWS trees was 18 percent greater than the trees receiving surface irrigation, enabling those trees to grow larger due to increased water, oxygen and nutrient uptake. Due to their root growth and root mass, the RWS trees demonstrated the ability to quickly thrive after transplanting.