Tese microclovers blend well with various lawn grasses and require less frequent mowing than more traditional forage types. All of this while doing what legumes like clover do best, fix atmospheric nitrogen and return that nutrient to the turf-clover ecosystem. Tus, potentially, they reduce the need for frequent granular nitrogen fertilization.
So, what does the recent research on cool-season lawn grasses say? In one study (Sparks et. al., 2015), researchers in Kentucky evaluated three planting dates (May, July, September) to determine when the best time was to introduce clover from seed into an existing lawn. In that study, they determined that earlier in the season was better for clover establishment.
In another study, the growth, appearance/uniformity, and persistence of Microclover in a cool-season lawn mix as affected by supplemental nitrogen fertilization was studied in Indiana (Bigelow et. al., 2021). In this study, the researchers measured how clover inclusion and annual nitrogen fertilization at 2 pounds (0.907 kg) of N affected growth, appearance, and species composition with time. Tey found that the clover, when supplementally fed with granular fertilizer, resulted in the best overall green appearance (Figure 3) and most growth, which at times was excessive (e.g., clipping debris on the surface).
One of the take-home messages of this finding is that, if the goal is to have the clover supply much of the nitrogen nutrition, supplemental fertilizer should be minimized. Te study also showed that clover populations are often temporal. In other words, the stand’s composition changed with time. In this study, there was a decline in clover populations over the winter months for unknown reasons (e.g., cold temperatures, pests, etc.). Tus, to maintain a consistent polystand, some regular reseeding may be required.
In a last and most recent study (Boyle et al., 2024), researchers in Utah evaluated four different clover species for inclusion in a Kentucky bluegrass lawn turf fertilized with a total of 1 pound (0.454 kg) of supplemental nitrogen annually. Tese four clovers were: white, strawberry, crimson, and rose clover. Again, the aim was to see if these species might persist in that environment and if the clovers could also function as part of a self-feeding lawn. Tey found that, like the Indiana study, the grass- clover dicultures were a suitable alternative to a Kentucky bluegrass monostand. Additionally, supplemental nitrogen did not affect clover persistence, and there were differences among the clovers. For example, shredding and browning was observed where the crimson clover was used. Tis negatively affected the stand’s appearance at various points in the growing season. (Figure 4)
Figure 3. An overview of the grass-clover research plots in West Lafayette showing the effect of supplemental nitrogen on the lawn’s grass and grass- clover areas.
Figure 4. Tis is an overview of a turfgrass-clover stand in acute drought. In this case, the stand’s appearance is impacted by the turfgrass’ reaction to drought conditions as contrasted to the clover’s reaction to the same conditions.
Ultimately, all the above demonstrates that grass-clover lawns are feasible, but they also have challenges. Most notably, are public adoption and stand persistence.
References: Bigelow, C.A., G.A. Macke, K. Johnson, and D.S. Richmond. 2021. Cool-season lawn performance as influenced by ‘Microclover’ inclusion and supplemental nitrogen. Intl Turf Soc Res. J. 2021: 121-132.
Boyle, P.E., K. Kopp, X. Dai, B. Bushman, P. Johnson and P. Grossl. 2024. Clover (Trifolium spp.) inclusion in Kentucky bluegrass (Poa pratensis) lawns. HortSci. 59:1020-1026.
Sparks, B., Munshaw, G., Williams D., Barrett, M., Beasley, J., and P. Woosley. 2015. Preplant cultivation techniques and planting date effects on white clover establishment into an existing cool-season turfgrass sward. HortSci. 50:615-620.
Cale Bigelow, PhD, is a professor of Turfgrass Science and Ecology in the Department of Horticulture and Landscape Architecture at Purdue University in Indiana. Mike Fidanza, PhD, is a professor of Plant and Soil Science at Pennsylvania State University, Berks Campus. They are teaming to provide a Rooted in Research article for each issue of Turf News. All photos courtesy of Dr. Cale Bigelow
58 TPI Turf News September/October 2025
Page 1 |
Page 2 |
Page 3 |
Page 4 |
Page 5 |
Page 6 |
Page 7 |
Page 8 |
Page 9 |
Page 10 |
Page 11 |
Page 12 |
Page 13 |
Page 14 |
Page 15 |
Page 16 |
Page 17 |
Page 18 |
Page 19 |
Page 20 |
Page 21 |
Page 22 |
Page 23 |
Page 24 |
Page 25 |
Page 26 |
Page 27 |
Page 28 |
Page 29 |
Page 30 |
Page 31 |
Page 32 |
Page 33 |
Page 34 |
Page 35 |
Page 36 |
Page 37 |
Page 38 |
Page 39 |
Page 40 |
Page 41 |
Page 42 |
Page 43 |
Page 44 |
Page 45 |
Page 46 |
Page 47 |
Page 48 |
Page 49 |
Page 50 |
Page 51 |
Page 52 |
Page 53 |
Page 54 |
Page 55 |
Page 56 |
Page 57 |
Page 58 |
Page 59 |
Page 60 |
Page 61 |
Page 62 |
Page 63 |
Page 64 |
Page 65 |
Page 66 |
Page 67 |
Page 68 |
Page 69 |
Page 70 |
Page 71 |
Page 72 |
Page 73 |
Page 74 |
Page 75 |
Page 76 |
Page 77 |
Page 78 |
Page 79 |
Page 80 |
Page 81 |
Page 82 |
Page 83 |
Page 84
