ATA TURF TIMES: By Casey O’Neal, Graduate Research Assistant, Auburn University | Julie Wang, Graduate Research Assistant, University of Georgia | Nikolay Minaev, Graduate Research Assistant, Mississippi State University
Movements such as “Save the Bees”, “No Mow May”, and “Let it Bloom June” are recently trending critiques of monoculture lawns. They highlight the lack of plant and insect diversity in single grass species or cultivar lawns. In recent years, programs like Operation Pollinator have moved the golf industries toward stakeholder interests by supporting research and outreach efforts to improve the ecological function of turf on their facilities. Similarly, the turfgrass industry must prepare to do the same for lawns. While replacing grass lawns with flower gardens, white clover fields, or meadows may be beneficial for pollinators and people in some areas, it ignores the documented want and need for lawns in modern society.
Monoculture lawns, typically a green frame around residential and commercial buildings, accumulate pests and consume a significant sum of inputs. Monoculture lawn alternatives, such as diversified, pollinator friendly, or flower lawns have been discussed; however, a warm-season alternative lawn with known beneficial impact and best management practices (BMPs) has not solidified in science or common practice. Understanding BMPs, and the benefits of these lawns, are crucial goals for the future of the turfgrass industry. The United States Department of Agriculture-National Institute of Food and Agriculture (USDA-NIFA) has funded the Refuge Lawn project to help highlight these goals.
The Refuge Lawn project consists of interdisciplinary researchers from Mississippi State University (MSU), Auburn University (AU), and the University of Georgia (UGA). The team set out to identify low-growing, flowering plants that would be easily established and managed in grass lawns, as well as provide the resources necessary to promote an abundant and diverse pollinator community. As some of the graduate students work on different aspects of the project, we would like to share some of our on-going research.
Picking the right plants
At Mississippi State University, Nikolay Minaev, working with Dr. Jay McCurdy, has been looking for flowering plants that could be easily established and propagated within turfgrasses commonly found in southeastern lawns. After evaluating various species based on their blooming properties and appearances in lawns, it was determined that spring beauty (Claytonia virginica) shows high potential for inclusion in warm-season lawns. Spring beauty is a perennial wildflower that is native to rich forests and low woodlands. It prefers moist, well-drained soil and light shade to part sun. It grows from a small corm or seeds. The growing season lasts from January through April in the temperate climate of the southeast, after which the plant senesces and lies dormant before emerging from corms the next year. The flowers are showy, pinkish white with deep pink veins, and open in clusters at the apex of the plant, adding a burst of color to the lawn during the early spring period. Additionally, it is a resource for pollinators such as the rare spring beauty bee, a small mining bee native to eastern North America.
The current understanding of spring beauty propagation is limited, hence we aim to address this knowledge gap by conducting a comprehensive study. The primary objective is to phenotype different populations of spring beauty and identify those with the most abundant and long-lasting bloom period, accompanied by high seed production and germination rates. This will allow for the selection of the most promising population for inclusion in lawns. In addition to identifying the optimal population, we are also exploring the most convenient method of propagation, with a particular focus on seeding. To achieve this, we are conducting experiments to find the optimal conditions for spring beauty germination, including testing various temperatures and probable treatments for quicker establishment.
Another project investigates the tolerance of spring beauty to commonly used pre-emergence herbicides in lawns. Our objective is to develop management practices that are safe for both turfgrass and spring beauty. By combining these different aspects of our research, we hope to provide a comprehensive understanding of spring beauty propagation and its integration into turfgrass lawns, while also promoting safe and sustainable management practices.
Caring for a refuge lawn
Julie Wang and Dr. Gerald Henry at the University of Georgia are investigating the BMPs for cultural management of a refuge lawn. Mowing height is one of the most well documented cultural factors affecting weed populations in turfgrass. Nearly all lawns are regularly mown for functionality and aesthetics. While mowing is relatively well understood in terms of eliminating weeds, it can be similarly applied to encourage flower production and growth of refuge lawn. As part of the Refuge Lawn project, we are studying the effect of mowing height on flowering plants commonly found in turfgrass that have potential to be pollinator resources. We are currently measuring the survival, growth, and reproduction of white clover (Trifolium repens), Virginia buttonweed (Diodia virginiana), and common lespedeza (Kummerowia striata) in response to different mowing heights. The results may explain the persistence of flowering plants in turfgrass as well as their potential as floral resources for pollinators.
Fertilization, another common cultural practice in lawns, affects species competition and plant diversity. A high nitrogen (N) content increases turfgrass productivity and competitiveness with flowering plants adapted to limited N availability. This is especially relevant as fertility practices vary by turfgrass species. For instance, centipedegrass (Eremochloa ophiuroides) is adapted to lower maintenance regimes in contrast with hybrid bermudagrass (Cynodon dactylon x C. transvaalensis) that requires regular fertilization during peak growth. We are evaluating the competition between common flowering plants and turfgrasses under different fertility treatments, focusing on white clover, Virginia buttonweed, centipedegrass and hybrid bermudagrass. Preliminary results suggest that low fertility inputs hinder hybrid bermudagrass growth, leading to an open canopy, which encourages flowering plant growth. On the other hand, exorbitant amounts of fertility on centipedegrass only enhances flowering plant competition and further plant growth. The understanding of flowering plant and turfgrass dynamics will help create BMPs for both homeowners and the turfgrass industry.
What do the bugs think?
At Auburn University, Casey O’Neal and Dr. David Held want to know what insects benefit from integrating flowering plants into warm-season grasses. Beginning in fall 2021, we established plots of seven potential flowering plant species in lawns at the AU Turf Unit, Town Creek Cemetery, and Kiesel Park in Auburn. These sites consist of established turfgrass lawns that host a range of common warm-season turfgrasses including bermudagrass and centipedegrass. The flowering species include spring beauty, white clover, and Virginia buttonweed, allowing us to connect our research with the teams at MSU and UGA. In 2022, the flowering sites were monitored for visitation by insect pollinators, and the insects were collected and identified. Due to the drought in 2022, data collection at these sites will continue in 2023. From these collections, we can establish a pollinator network. This network will show which flowering plants provide resources for the largest number of pollinators, and which plants provide resources for rare or threatened pollinators. While the exact number is unknown, it is expected that there are more species of bees in Alabama than any other southeastern state, and currently over 500 species have been identified in Georgia alone. With such a high diversity of insect pollinators, it is important to include flowering plants that serve as many of the native pollinators in the southeastern US as possible.
By combining the knowledge gained from our respective studies, we can establish a model refuge lawn with known BMPs and beneficial impacts on pollinators. To keep up with us and the rest of Refuge Lawn project’s work, or to contact any of the researchers involved, please visit our website at www.refugelawn.com.
This work is supported by Agricultural and Food Research Initiative grant no. 2021-67013-34145 from the USDA National Institute of Food and Agriculture.READ THE ISSUE