Southern California residents have long used tall fescue on their lawns, largely because it stays green during the winter. However, fescues lose color quickly during hot and dry conditions. With the growing water shortages, particularly in the summer in California, it has been hard to water fescue enough to keep it green during the hot months. As an alternative, bermuda lawns have been replacing fescue lawns across California, since bermudagrasses need less water in the summer to stay green. However, bermudagrasses go dormant and lose color with low temperatures during fall and winter. The ideal situation would be to develop a variety of bermudagrass that can keep the color during temperatures below 50°F and in dry periods.
This is the goal of a collaborative effort from Sod Solutions, Oklahoma State University and A-G Sod Farms: to identify a variety of bermudagrass for Southern and Central California that can take the heat and dry weather of the summer months and still maintain green color during the winter.
The program started in 2016, testing 100 experimental lines with three replications in Southern California. After two years of testing the 100 experimentals, the best materials were selected based on their cold and drought tolerance. A total of 11 best performing experimental lines were advanced and were tested in two locations: Nuevo (Southern California) and Selma (Northern California). For the first two years of evaluations, the plots were only 4 x 5 ft, but for the second phase of testing, the plots were larger, to allow better visual evaluations. The bigger plots were exposed to a dry period in 2020: they received no water for almost 60 days and performance and green color were evaluated at the two locations. The best four materials were selected, based on their speed of growth, winter color and green color during the dry down period. These four experimental lines are:
These experimental lines were planted in June 2021 near Nuevo and Fresno. They were planted into 20 x 25 ft plots to allow harvesting. Then the harvested sod pieces had their sod strength measured by a device. Now that the harvesting test is completed, the plots will continue to be maintained as a regular sod field; watered, fertilized and mowed. The regrowth will be monitored and recorded. After plots are mature, the experimental lines will be exposed to a dry down period and their drought tolerance evaluated one more time. The goal is to have a new variety that has not only improved cold and drought tolerance, but also blocks well (good sod strength) and regrows fast. The last evaluation is scheduled for summer 2022.