By Charlotte Lorick
Charlotte Lorick is the Head of Biodiversity Conservation at the Oak Spring Garden Foundation in Virginia, United States. She also leads the Forgotten Flora Project, an environmental and educational consulting initiative. In addition to this work, she serves as a co-lead of the Restorative Landscape Coalition, a working group of the Northeast Seed Network. In this blog, she shares her hands-on experience organically restoring a meadow in a former horse pasture and hayfield in the eastern United States.
In Virginia’s Northern Piedmont region, where rolling hills extend from the Blue Ridge Mountains toward the Atlantic Coastal Plain, sits the Oak Spring Garden Foundation (OSGF). Its mission is to support and inspire scholarship and public dialogue on the history and future of plants, including the art and culture of plants, gardens, and landscapes, and the importance of plants for human well-being. OSGF advances this mission through fellowship and residency programs, a renowned research library, and by cultivating a biocultural conservation farm and ornamental gardens. The foundation also convenes meetings and collaborations focused on botany, horticulture, and landscape conservation. In this capacity, OSGF hosted the inaugural meeting of the Restorative Landscape Coalition in 2024.
Among the foundation’s primary goals is conserving and promoting native plants and biodiversity across the 280-hectares (700-acres) of land under its care. This goal can often prove challenging because the land at OSGF, like much of the rich soils of the Northern Piedmont, has long been shaped by agricultural land use. The impacts of agriculture on soil and plant communities are long lasting and can be detrimental to native species richness and diversity. Heavy fertilization favors exotic species over natives and the common practice of heavy tillage forever alters the soil and seed bank, further decreasing native species richness. Indeed, the IUCN considers temperate grasslands the least protected, most heavily altered, and most endangered terrestrial biome in the world. In the southeastern United States in particular, an estimated 90% of pre-European grasslands have been lost due to agricultural practices and other factors. And the small amount that do remain are indicators of the incredible species richness that have been lost. A recent study of Virginia’s Piedmont grasslands demonstrates they are far more biodiverse than previously documented, with surveyed sites having over 100 plant species in a single 100 m² plot.
This ecological and land use legacy raises a common challenge for conservation landowners across our region: how to restore native meadows to ecosystems degraded by intensive agriculture? As agricultural abandonment has increased across the region, converting old pastures to native meadows by removing existing vegetation and seeding a regionally native seed mix has become a common practice to address that challenge. Meadow restoration as a practice can actually mean different things depending on the situation. In the context of the Society for Ecological Restoration’s (SER) Restorative Continuum of activities, most often these kinds of meadow plantings fall along the restoration continuum but are distinct from efforts to fully restore native biodiversity and ecosystem health based on a reference ecosystem. Instead, in our region and at OSGF these meadow restorations emphasize incorporating designed, site-adapted native plant communities into degraded grasslands. We are aiming to increase native diversity in our grasslands and this is one way to accomplish this. However, for several reasons, including lack of robust data on reference communities or access to hyperlocal native seed, we consider these projects as distinct from but complementary to a full-scale ecological restoration effort.
As every practitioner will tell you, restoring a native meadow is a challenging process in this region as the non-native weeds and pasture grasses (that had historically been introduced for cattle and hay production throughout the Eastern US) are tenacious. Removing them effectively to allow establishment from a native seed mix is arguably the most critical yet most challenging part of the meadow restoration process. Conventional methods rely on heavy use of herbicides or tilling, which both have considerable downsides. Yet data are lacking in this region specifically on alternatives. To address this gap and inspire formal research on innovative or alternative techniques to restore native meadows in the Eastern US, in 2023 we trialed a novel method to restore a meadow that could prove a viable alternative for small areas to the conventional herbicide and tillage approaches.
This post details our project, outcomes, and lessons learned. We outline the experimental approach, site preparation methods, and early establishment results, and reflect on the practical implications of this technique. This project is a case study rather than a formal experiment, but we believe that what we learned in the field and are sharing here can havevalue for generating hypotheses and informing land managers interested in applying this method on their land and researchers interested in conducting future studies.
Landscape Context and the Case for Meadow Restoration
The OSGF landscape includes a rich mosaic of open fields, meadows, forests, streams, and wetlands that have been shaped by a long history of anthropogenic influence. In Pre-settlement times, the commonly held theory is that the Piedmont was characterized by oak-hickory landscapes with patches of forest and savannahs often managed by controlled fire. Post European settlement, the land at OSGF was managed, including by enslaved people, for row crops and apple orchards, grazing cattle and hay production, and, in the last 50 years, horse pasture.
Today, through careful inventory of the landscape, we have identified several remnant and globally rare plant communities on the OSGF property that seem to have escaped much of the human impacts. These include a Piedmont upland depression swamp containing cypress-knee sedge (Carex decomposita), a species designated as critically imperiled in Virginia with fewer than five known populations remaining in the state, and false hop sedge (Carex lupuliformis), another exceptionally rare species.
However, most of the open fields on the property are now products of a two and a half century agricultural legacy and are low in diversity, dominated by non-native cool-season grasses and other exotic species. While these non-native grass dominated pastures are actually choice nesting areas for many declining grassland specialist bird species at OSGF (including Eastern Meadowlarks (Sturnella magna), Grasshopper Sparrows (Ammodramus savannarum) and Bobolinks (Dolichonyx oryzivorus), we are selecting areas carefully to convert to native meadow where these birds are not nesting to support other suites of species that benefit from native meadow conversion. These areas hold strong potential for ecological restoration and conversion to diverse native meadow habitat and have become high priorities for conservation for OSGF. For example OSGF is also home to several threatened or declining bird species that depend on diverse grasslands and early successional plant communities. These species include Short-eared Owl (Asio flammeus), Northern Bobwhite (Colinus virginianus), American Kestrel (Falco sparverius), Savannah Sparrow (Passerculus sandwichensis), and Henslow’s Sparrow (Centronyx henslowii). Notably, the native meadows that OSGF has established over the years have become winter hotspots for Short-eared Owls and Northern Harriers (Circus hudsonius) and other birds.
Can Sod Removal Replace Herbicides?
As OSGF transitions away from its historic use of the land for hayfields and pasture, we have initiated several native meadow restoration projects over the past decade, totaling roughly 24 hectares (60 acres). These projects have primarily used conventional installation approaches, including herbicide application or chemical-free methods such as repeated tilling and plowing. The most common conventional method is to apply a broad-spectrum herbicide, such as glyphosate, at least 3 times to create enough bare ground to seed the meadow. But chemical herbicides are not always effective on some of the most aggressive weeds, they are not effective on controlling weed seeds in the seed bank, they can alsonegatively alter the soil, and pose safety concerns for humans and wildlife. Unfortunately the common organic alternative relies on heavy tillage which comes with its own major downsides, including increases in noxious non-native weeds and negative impacts on soil health.
OSGF is particularly interested in restoration strategies that minimize or avoid the use of chemical herbicides. We are not alone. Across our region, many landowners are exploring herbicide-free approaches to meadow restoration. However, robust data on the efficacy of alternative methods are limited.
For this project we decided to try sod removal or scraping. Although this method of site preparation is often employed on small scales for garden installation or lawn conversion, we found little data on this method for large scale restoration plantings. However, we were encouraged by the results of some restoration studies from Europe and California involving topsoil removal.
Sod Removal Project Design: Methods, Site Preparation, Seeding, and Maintenance
The sod removal trial was designed with two main goals: to test an understudied organic approach to meadow restoration site preparation, and to share our case study to encourage further exploration of the approach, and perhaps formal research comparing this method with more common approaches.
The trial took place on a 0.8-hectare (2-acre) parcel of a former horse pasture and hayfield. Baseline vegetation surveys showed it was dominated by introduced cool-season pasture grasses: tall fescue (Lolium arundinaceum), orchard grass (Dactylis glomerata), and Kentucky bluegrass (Poa pratensis).
To track change over time, we established permanent vegetation monitoring plots across the site. Vegetation surveys were conducted at baseline (Year 0) before disturbance and twice per growing season following seeding (2024 = Year 1, 2025 = Year 2). Soil samples were also collected at baseline and in each subsequent year. In November 2023, we removed the top layer of sod using the bucket of a skid-steer at a depth of approximately two inches. Afterward, the soil surface was lightly raked to improve seed-to-soil contact. We hand-broadcast a native seed mix using pine shavings as a carrier at 13.5 kg per hectare (12 lb per acre) and seeded a temporary cover crop of 50% winter rye and 50% oats at 34 kg per hectare (30 lb per acre). The field was then lightly covered with straw using a straw blower. The seed mix included 28 regionally appropriate species, roughly 60% perennial grasses and 40% forbs.
Management during the first two years was intentionally light. In Year 1, the cover crop was flail-mowed once in the spring. Other interventions involved manual cutting or pulling of problem weeds, primarily biennial thistles (Carduusspp.), a single clump of Johnsongrass (Sorghum halepense) likely introduced during site preparation, and spot mowing of creeping thistle (Cirsium arvense). Additional mowing had been planned but proved unnecessary due to relatively low weed pressure. The most common weeds were the annual grass Setaria pumila, which we expected to decline naturally, and white clover (Trifolium repens), which remained low-growing and did not appear to inhibit germination of the native seed mix. In Year 2, the meadow was flail-mowed once in the spring, followed by two days of manual cutting of problem weeds—mainly biennial thistles—to prevent seed set during the growing season.
Progress photos
Preliminary but Encouraging Outcomes
Because native meadows take time to establish, we want to emphasize that these observations are preliminary, with only two growing seasons documented so far. We will continue monitoring the site over the coming years and hope to share longer-term results as the meadow develops.
Nevertheless, at this early stage, several encouraging patterns have emerged. Total native species richness approximately doubled in Year 1 and tripled in Year 2 compared to baseline conditions. Native forb richness increased even more dramatically, more than tripling from baseline to Year 2. At the same time, the three most abundant baseline species—all exotic cool-season grasses—dropped from nearly 100% cover in Year 0 to less than 5% cover by Year 2 when averaged across all survey plots. This is an important indicator that sod removal was extremely effective in removing existing non-native vegetation.
By the second year, 22 of the 28 species in the seed mix had germinated, with several species already fruiting in the first year. This is a highly successful germination result by year two. For comparison, some of our other meadow restoration projects that used herbicide did not have germination of many of these same species until after year 2.
In addition to the seeded species, we documented a number of native volunteer species that were not part of the seed mix and were not recorded in baseline surveys. These included secund rush (Juncus secundus), path rush (Juncus tenuis), forked rush (Juncus dichotomus), sweet everlasting (Pseudognaphalium obtusifolium), green milkweed (Asclepias viridiflora), and sedges such as fox sedge (Carex vulpinoidea), straw-colored flatsedge (Cyperus strigosus) and globe flatsedge (Cyperus echinatus). The arrival of native volunteer species was an exciting bonus and good indicator that some of the legacy native seedbank was still intact and uncovered with sod removal.
Lessons Learned and Key Takeaways
While this project was not designed as a formal experiment, the results have been striking and our hypotheses can inform further studies. Compared to other meadow restoration efforts attempted at OSGF, this planting has performed exceptionally well. It has required far less maintenance and weed management, and the native seed mix established with noticeably higher germination, flowering, and overall cover. The method was also particularly effective at suppressing the dominant cool-season grasses that often make meadow establishment so challenging.
Before seeding, the site supported very little native diversity. And the few native plants that we did find were woody seedlings or ruderal species such as horse-nettle (Solanum carolinense) and pokeweed (Phytolacca americana). Following the restoration work, native forb diversity increased substantially, including the appearance of several volunteer species. Although non-native white clover became the dominant plant by percent cover, its low, spreading growth did not appear to suppress the emerging native seedlings.
Of course, many factors could have contributed to this success. The seed was broadcast rather than drilled, which may have supported quicker germination. Careful site selection, existing vegetation conditions, and even the drought that followed seeding may also have played a role. Still, after more than a decade spent surveying and working in meadows across Virginia, this site stands out as one of the most rapidly successful restorations I’ve ever observed.
Our working hypothesis is that scraping away the existing sod removed much of the weed pressure by removing the grassrhizomes in the uppermost soil profile and some of the associated seed bank. It also slightly reduced the organic matter and nutrient layer at the soil surface—conditions that may have favored native species during establishment by reducingweed pressure (which thrive in more fertile soil). Although a decrease in organic matter may not be ideal for overall soil health, the decline is likely temporary. A growing body of research suggests that over time, the increase in native plant diversity may ultimately improve soil health beyond what we observed at baseline. This is something we plan to monitor in the years ahead with continued soil sampling.
The primary drawback of this method is cost. Removing and relocating large amounts of topsoil requires significant upfront investment, which may be impractical in some situations and at larger scales. However, this material can be reused elsewhere on a property in areas not prioritized for restoration or offered as a resource to farmers or composting operations. It is possible that these higher initial costs could ultimately be offset by reduced long-term maintenance and weed control, but that would take further study to determine.
Another challenge we encountered was sourcing local seed. Ideally, we would have used seed with documented provenance sourced from populations occurring in Virginia’s Northern Piedmont ecoregion, but the native seed supply chain still has significant gaps. To help address native seed shortages, OSGF has partnered with the Northeast Seed Network’s Mid-Atlantic Seed Partnership and the Restorative Landscape Coalition, a working group of botanic gardens, arboreta, seed banks, and allied organizations working to expand the availability of diverse, source-identified native seed for ecological restoration across the Mid-Atlantic and Northeastern United States. For this project we purchased seed from Ernst Conservation Seed in Pennsylvania and although not all seeds were sourced from our ecoregion, we were pleased that all their seed was from very nearby ecoregions and states in the Eastern US.
We hope this project encourages others to explore sod removal for meadow restoration. There is much practical experience still to be gained and there are many questions worth investigating in controlled experiments to compare this method with other site preparation techniques, test different sod removal depths, or variations in seed mix compositions.
In the meantime, we plan to explore the further use of this approach in future restoration projects at OSGF. If you’re curious about the project or interested in collaborating, we’d be happy to connect.
Please feel free to reach out to me at charlotte.lorick@osgf.org, and stay up to date with the outcomes of this project—and more of my work—at https://www.osgf.org/conservation-biodiversity and https://forgottenfloraproject.substack.com/.
Acknowledgements: Special thank you to OSGF team Clif Brown, Josh Rector, Katharine Perkin, Sarah Krementz, Sam Terry and local contractor Virginica LLC for support of this project.