A recent study by the University of Arizona's School of Plant Sciences has found that root watering irrigation products help tree and shrub root systems become established more quickly.

Study finds deep-root watering generates 48% more deep-root growth in transplanted trees

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 root zone.

“One of the key design goals for the RWS product line was to help trees and shrubs survive transplant shock,” said Rick Foster, senior product manager for Rain Bird’s Accessories Strategic Business Unit. “Trees are one of the most valuable investments in a landscape project.  Protecting that investment is important to our customers.  The University of Arizona study demonstrates and quantifies how deep root watering using the RWS products can increase a tree’s chances of survival.”

Rain Bird’s RWS products include a patented basket weave canister which enables below ground irrigation to a depth of up to 36 inches. In addition to promoting faster and deeper root growth, water efficiency is achieved by greatly reducing loss due to evaporation and run-off typical of surface irrigation. These pre-assembled, ready-to-install devices are available with bubblers offering different precipitation rates.  Models are also available for use in drip installations.

Plant scientist and researcher Dr. Ursula Schuch conducted the RWS study for the University of Arizona’s School of Plant Sciences. The study examined the growth, establishment, and survival of 48 ash trees transplanted at a test site in Tucson, AZ. Half of the 8-foot-tall trees were each irrigated with a pair of Rain Bird® 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 3, 8 and 13 months after transplanting to collect data for the study.

The study found that just three months after transplanting, the trees irrigated with Rain Bird’s 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.

“Dr. Schuch’s study is extremely important because it demonstrates one of the key benefits of our Root Watering Series products,” Foster said. “Regardless of whether a site has transplanted 5 or 500 trees, the RWS enhances each tree’s chance of survival, helping it grow new roots more quickly and minimizing the need to purchase and plant costly replacement trees.”