By Robert Graham
Early secondary successional habitat is hard to find in central Massachusetts. Even the immediate area surrounding New England Botanic Garden at Tower Hill is mostly undisturbed Department of Conservation and Recreation watershed protection zones. Here at the Garden, we maintain more than 20 acres of early successional meadow habitat in a variety of forms, from dry, highly disturbed parking lot island meadows where vetch (Vicia spp.) and garden bird’s-foot trefoil (Lotus corniculatus) aggressively try to take over newly established seed, to wet meadows full of willow (Salix spp.) and Joe-Pye weed (Eutrochium spp.). With the variety of habitat types present on the property, as well as a large area to experiment in, I’ve gotten the chance to use a variety of meadow install and management strategies over the past few years.
Property and Management History
Like much of historic Massachusetts, records indicate that New England Botanic Garden’s nearly 200-acre property was farmed at least as far back as the 18th century. Our 1740s farmhouse, historically known as the “Elisha Maynard House,” in the center of the property serves as the most evident example. Stone walls dating back to the 1800s cross all over the property separating former pastureland. The pasture was grazed by dairy cattle until 1946 when it was transitioned from commercial agriculture to a simple gentleman’s farm. The property has only operated as a public botanic garden since 1986 when it was purchased by the Worcester County Horticultural Society as its main base of operations. In addition to the structures, we see this farm history throughout the garden landscape, from successional white pine forest dominating the canopy in the naturalistic gardens that were once pasture, to soil compaction in our meadows from years of grazing dairy cows. Up until the last few years, the meadow property was maintained primarily by yearly fall mowing with little to no other management. Over the last five years the garden’s staff have taken on more involved meadow management strategies that help promote native plants and provide pollinator and wildlife habitat.
created by dji camera
Image 1: The Garden used to maintain a large volume of mown turf. In the last few years, many of these former turf spaces and new construction areas have been successfully transitioned into meadow habitat.
Installing and Transitioning to New Meadows
I’ve been involved in a variety of different meadow installations in recent years, from small scale 1/10th acre former lawn areas to 6+ acre post-construction installations. Meadow installations big or small can be a huge undertaking. Long-term, well-established meadows fit the bill for the “low maintenance” garden that we all hope for, but they can require a large amount of involvement to get to that point. To start, I want to cover small scale meadow installations, briefly reviewing some of the meadow installation types because they can be an important part of future meadow maintenance.
Under one-acre meadows are the most prevalent and easily obtainable here in central Massachusetts. From small commercial lots to home gardens, spaces of this size are available for providing early successional habitat. One method we have used for small meadow installations in formerly mown grass areas is to remove the sod layer with a sod cutter to expose bare soil. We then rake out the newly exposed soil and install native seed by hand. Salt marsh hay is then spread over the new seed material. Salt marsh hay is a great resource when installing new seed. It is weed free hay that covers the seed and protects it from bird and animal foraging. It also helps to prevent movement of the seed from rain and wind. For immediate results, removing the sod layer is hugely beneficial. This step allows the seed to germinate with little to no competition other than recruitment from invasive seed and allows for quicker establishment of the newly installed seed in the meadow. This process is one of the best for quickly establishing a small meadow.
In more recent installations with bare soil, instead of simply using salt marsh hay, we’ve used an erosion control blanket. Erosion control blankets are rolled natural fiber blankets that both protect new seed and prevent surface erosion on bare soil. The biodegradable mesh and fiber is easy to keep in place with biodegradable stakes, and it allows seed material to grow through while preventing surface soil movement. As an added benefit, it makes it obvious to guests that an area was recently renovated. With the volume of foot traffic we get at the Garden, making our delicate new meadows obvious is necessary to prevent newly established plants from being crushed underfoot. I’ve used multiple different types of erosion control fabric and have had the most success with the “Curlex II erosion control blanket” by the American Excelsior Company. It is made from sustainably harvested aspen fibers and is far and away the easiest blanket I’ve worked with. It holds its shape well, doesn’t produce dust like many of the sawdust style erosion blankets, and doesn’t begin to start degrading for 90 days, which gives the seed plenty of time to germinate without soil movement.
Image 2: A new meadow created on the site of a closed path. An erosion control blanket was used to keep the new meadow soil and seed in place.
The only concern I have about removing the sod layer is the amount of soil disturbance it can cause. For the area of property we were working in, this method was the right choice. For numerous other small meadow area installations I’ve done both at the Garden and offsite, I’ve gone a different route, smothering the sod or other undesired weed growth with cardboard. This method is quick and easy for small meadow installations, and it protects the native soil. I still like to use an erosion control blanket to protect the newly added soil and seed, but this method is faster, less involved, and the perfect solution for small scale meadows.
For larger meadows we’ve used three different strategies.
- Bare Soil Post-Construction Hydroseeding: This strategy was employed for a large-scale meadow renovation that involved earth-moving equipment and a lot of soil disturbance. This type of meadow requires the most management from the onset. Disturbed soils are an easy target for invasive seed recruitment that can take over the newly disturbed soil. The biggest hurdle with this type of meadow is making sure the wildflower mix (we used New England Wetland Plants seed mixes) gets a chance to germinate, flower, and drop new seed before any weed seed. There is also a huge erosion control concern especially on slopes. Bare soil easily moves and can take target seed with it.
- Seeded Former Turfgrass: This strategy was employed to convert former turfgrass areas to diverse meadow and included the addition of desirable plant species from seed. We used a conservation seeder, which allows meadow seed to be introduced to the soil layer without disturbing the root layer of the newly transitioned turf. This installation method allows for easy maintenance with no concern of seed movement or soil erosion. The biggest hurdle with this method is competition between the desired meadow mix and cool season grasses that are well established in the new meadow area.
- “Letting Grass Go:” This strategy was employed to convert former turfgrass areas to diverse meadow but did not include the addition of desirable plant species from seed. This method is the least involved of all meadow establishment techniques. Establishment relies on the seed bank in the area and a change in maintenance intervals. It can take years for target wildflowers and grasses to reoccupy the meadow. At the Garden, we have many bordering meadows close to the new meadow areas dropping wildflower seeds. If this method was used in an area with nothing but turfgrass it could be extremely difficult to establish a meadow naturally with little to no involvement.
Image 3: New post-construction meadow going into its second year.
Image 4: New meadow being installed in the orchard using a conservation seeder. This type of seeder presses seed under the surface of the meadow with a spike and a roller. This allows the existing root zone of the meadow to stay intact.
Image 5: Former turf area left alone and allowed to re-establish as meadow with no new seed introduction. By year two and three, populations of goldenrod (Solidago spp.), little bluestem (Schizachyrium scoparium), and wild strawberry (Fragaria virginiana) are apparent.
Meadow Management
When it comes to long term management of meadow habitat, I like to try to stay as uninvolved as possible. However, in order to promote early secondary successional habitat, there needs to be some kind of disturbance. For the last few hundred years, the primary disturbance type at the New England Botanic Garden property has been pasture grazing of livestock. When that primary disturbance type stopped in 1986 after the property was transitioned from farm to garden, a new type of disturbance – mowing – was needed to keep intermediate succession species like trees and shrubs from establishing in the newly unmaintained areas. At the Garden, we opt for “mechanical management” techniques whenever possible. I try to primarily not use any herbicide in the majority of my grounds management strategies, but there are times when we will use targeted cut and paint herbicide techniques on large, well-established populations of invasive species like bittersweet (Celastrus orbiculatus).
Mowing is a great way to keep woody material from establishing itself in meadows. Meadow management is a constant balance between creating early successional habitat, promoting native species, and eliminating invasive species. Maintaining specific mowing intervals is the most important management strategy I employ here at the garden. When I started in 2017, the mowing cycles used in the meadow were simple. All meadow types present on the property were mowed in the fall before snowfall. This style of mowing is not too dissimilar from the mowing methods used in small scale agriculture pastures across much of central Massachusetts and New England.
Former to Current Practices
Single cut fall mowing was an effective strategy we used here at New England Botanic Garden when we had limited staff hours to manage the acres of meadows present on the property. Fall mowing does have a few benefits:
- Helps keep invasive species and woody material from fully establishing in the meadows.
- In general, the ground is dry. In wet conditions, compaction is permanent. Once a machine sinks into soft wet soil, the damage done to the structure of the soil is irreversible. Typically, the only remediation to this damage is tilling, which is effective at loosening the soil but also destroys the well-established root zone that was present stabilizing the soil.
- Fall is the end of the growing season. With one late season cut, all future maintenance for the season is finished until next fall, and the meadow establishes itself on its own starting in spring.
Up until the last handful of years, this was our standard meadow management “plan.” It is an effective meadow management strategy in the sense that it provides early successional habitat with continued disturbance, and it keeps invasive species at bay. However, currently at the Garden, we can dedicate resources and time into a more involved meadow management strategy.
Spring vs Fall Mowing
Spring mowing is starting to come into favor as the preferred time of year for large scale meadow mowing to help protect overwintering pollinator habitat. In areas where this is possible (like dry upland meadows), it is the best method for overall habitat health. At New England Botanic Garden, I have a lot of trouble with spring mowing due to how high our water table is and the large density of wet meadows present on the property. I mow many of our upland meadows multiple times throughout the spring in order to knock back cool season grasses and invasives to give more room for warm season grasses and native wildflowers to thrive.
In areas where fall mowing is the only option due to the risk of soil compaction, I do a few things to help wildlife and plant habitat.
- Mowing as high as reasonably possible with the brush mower. If I have to mow an area due to a large amount of fall cool season grasses growing or invasive species taking over, I keep the blade as high as I can to protect as much pollinator habitat as possible. (Learn more about the right way to leave stems for native bees through Ecological Landscape Alliance.)
- Leaving wildlife islands. I like to leave big areas of untouched meadow in spaces where I perform fall mowing. I tend to leave areas where milkweed seed has not fully ripened and areas where there is no risk of invasives standing for winter. This creates protected winter habitat for plants, pollinators, native mammals, and winter birds.
Image: 6: Area of fall mowing was done with wildlife islands where common milkweed (Asclepias syriaca) has not finished going to seed.
Image 7: The same small patch of common milkweed protected on a wildlife island a few years later. With the proper mowing interval, the common milkweed (Asclepias syriaca) now takes up a one-third acre patch in the meadow.
Building New Meadows with Bare Soil (Post-Construction)
These meadows can be initially one of the most difficult meadow types to manage in their first few years due to the lack of a built-up seed base and the shifting of soil due to the lack of a well-defined root layer controlling soil erosion. There are two meadows at New England Botanic Garden that fit this description as post-construction meadows: the “parking lot meadow” and the “mountain view meadow.” Both these meadows are going on their third year after the recent renovation of the Garden’s expanded parking lot. After the soil movement was stabilized, both meadows were hydroseeded with seed mixes from New England Wetland Plants. Some of the predominant species in the mix include little bluestem (Schizachyrium scoparium), partridge pea (Chamaecrista fasciculata), wild rye (Elymus spp.), and marsh blazing star (Liatris spicata). In the early establishment of the meadow, we saw quick germination of partridge pea and wild rye but had little showing from the rest of the planted seed. At the same time of germination of planted seed, we saw quick growth of species like ragweed (Ambrosia artemisiifolia), Pennsylvania smartweed (Persicaria pensylvanica), and crabgrass (Digitaria spp.).
Year One
Problem Species: Pennsylvania smartweed, ragweed, crabgrass, field bindweed (Convolvulus arvensis), Japanese hops (Humulus japonicus).
Our primary management strategy in year one of the “parking lot meadows” was hand pulling/weeding. For a small meadow, this is the most effective strategy for removing non-target species to prevent further growth of root structure and keep them from going to seed. Hand pulling also allows meadow managers to be mindful of the delicate planted seed in the area. Especially with freshly turned soil, year one is the best time to try to eliminate as much non-target plant material as possible as the soil is still loose, and weeds aren’t well established.
In the larger open space of the “mountain view meadow,” hand pulling is unreasonable, so instead, I mow with our brush mower at its highest height in areas where we had little germination of intentional seed. This choice was a cost benefit analysis. Inevitably some of the target seed, which at the time of mowing was partridge pea, would be affected. The benefit was preventing the further spread of weed seed dispersed throughout the meadow by mowing the newer, establishing weed population before it could drop more new seed.
Year Two and Three
Problem Species: Hairy vetch (Vicia villosa), purple crown vetch (Securigera varia), bird’s-foot trefoil (Lotus corniculatus), garlic mustard (Alliaria petiolata), sweet clover (Melilotus spp.), mugwort (Artemisia vulgaris), dock (Rumex spp.).
As with all native wildflower meadows, competition from non-native plants will always be a problem. In our case, we had what seemed to be limited germination in year two. Thanks to repeated hand pulling efforts, much of the original problem species did not reappear (primarily the Japanese hops and ragweed). In order to protect any lingering seed from the original mix, we continued with hand pulling efforts in the parking lot areas. The involvement we had in the meadow was fairly minimal other than basic general maintenance of common invasive species like bittersweet (Celastrus orbiculatus) and multiflora rose (Rosa multiflora). In the “mountain view meadow,” we saw poor second year germination of newly generated or existing target seed material. This meadow stayed primarily untouched for its second year to prevent unnecessary soil disturbance and allow for any remaining desirable seed to germinate.
In the early months of the year three growing season, we saw quick establishment of “naturalized” species like red clover (Trifolium pratense) and white clover (Trifolium repens). Though our goal for our meadows is always promoting native species, in some cases leaving naturalized species like red and white clover is beneficial to the long-term establishment goals of the meadow area. The clover helps stabilize the still loose meadow soil, fixes nitrogen, and simply looks nice and green. I find the clover doesn’t compete heavily with the seed mix and it also allows other material to readily grow through it. The plants that I find to be an issue in the space are primarily other “naturalized” species such as crown vetch and bird’s-foot trefoil. Both these plants have bright spring color and to most people look beautiful, but I find they form dense mats that compete with everything in the area and prevent the native plant material from establishing.
For small meadows that have these dense mat-forming plants, hand pulling is effective. Forestry clearing saws and string trimmers are my favorite tools for year-round meadow maintenance. I use them in a few different ways and for a few reasons. While I refer to this as another form of “mowing,” this is not the same as mowing with a tow behind or walk-behind brush trimmer. It allows your work to be much more targeted. Some of the best uses of this equipment is for:
- Mowing flower heads off biennial weeds and other garden weeds to prevent them from going to seed. This does not eliminate the entire plant, but it can prevent seeds from being dispersed. In the case of plants like dock and bittersweet, cutting can prevent a large volume of new plants from being generated. Selective cutting when the plant is expending the most amount of energy provides a chance to exhaust the plant’s energy and ultimately eliminate it without having to use hand pulling or herbicide.
- Mowing in areas with new or sensitive soil. The “parking lot meadow” has many areas with either loose soil, or steep slopes. In this situation I would much rather mow the weed plant down repeatedly instead of creating soil disturbance and potentially uprooting germinating seed.
- Mowing areas that will never be able to be maintained with a ride-on mower. These include small meadows and meadows intermingled with woody material, obstacles like light poles, or meadows on steep slopes that can’t be maintained with a ride-on mower. Using a string trimmer or brush blade makes it possible to mow down weed material and make space for native seed to germinate.
Image 8: Year three post-construction meadow in late June. Heavy presence of black-eyed Susan (Rudbeckia hirta) growing over naturalized species clover (Trifolium spp.), and patches of bird’s-foot trefoil (Lotus corniculatus) still present underneath the target plants.
Image 9: Lance leaf coreopsis (Coreopsis lanceolata) and wild rye (Elymus spp.) successfully germinating year three in the parking lot island meadows over clover and hairy vetch.
Image 10: Stewardship staff member mowing crown vetch and dock out of the “Mountain View Meadow” using our battery powered forestry clearing saw. Wachusett mountain is visible in the background.
Large, Primarily Dry Upland Meadows
Problem Species: Bittersweet, multiflora rose, blackberry (Rubus spp.), fox grape (Vitis labrusca), non-native cool season grasses, crown vetch, common vetch, whorled bedstraw (Galium mollugo). Note: fox grape and most blackberry species are northeast native plants and thrive in meadow habitat. The only reason they are listed as potential problem species is thathey spread quickly across an area and can form thick monocultures. To encourage more diversity, I manage how these species spread to still allow them to succeed, just not aggressively take over the area.
Upland meadows are, in my opinion, the easiest to maintain overall. There is much less concern about soil compaction from use of mowing equipment and mowing can be done at many different times of year and growth periods. This drier soil also allows for use of larger seeding equipment at different times of year to introduce more native seed. However, these meadows are the ones most frequently mowed on our property due to the large density of invasive and non-native species that also do very well there.
In the dry meadows, I mow very frequently in spring to combat cool season grasses and invasives. Starting in early May, when the meadows are still moist and not ready for heavy equipment traffic, I use a string trimmer or brush blade to reduce early non-natives that show up. I target early blooming noxious weed species such as garden yellow rocket (Barbarea vulgaris) and garlic mustard (Alliaria petiolata) before they go to seed. In late May to early June, depending on when soil conditions allow, I start mowing all of the dry uplands meadows to help combat cool season grasses, crown vetch, and other common vetch species that are growing quickly in early spring. My thought process on this is ideally catching these species before they go to seed, and over time this can help prevent new non-target seed recruitment. It also gives the warm season grasses and native wildflowers a chance to grow without as much competition. Wherever possible, I avoid mowing areas that have native species already well established, like large stands of goldenrod (Solidago spp.), fleabane (Erigeron spp.), or milkweed (Asclepias spp.). When mowing, I pay very close attention to the areas I’m working in and am actively trying to identify native material starting to grow so I can avoid these plants whenever possible.
Image 11: Selective spring mowing in the Garden’s daffodil field meadow. I selectively mow areas in the spring that are primarily crown vetch and whorled bedstraw. The patches intentionally left are primarily goldenrod, and blackberry.
Wet Meadows
Problem Species: bittersweet, multiflora rose, autumn olive (Elaeagnus angustifolia), red maple (Acer rubrum), and purple loosestrife (Lythrum salicaria).
Wet meadows are the meadow type that I’m the most careful around. They are difficult to maintain because of their delicate, easily compacted wet soils. In general, I try to leave these meadows untouched for multiple years at a time. Because of the wet environment, I find that invasive species are a little slower to take hold in the area and are easy enough to target with the forestry clearing saw. When I have to mow, I wait until the ground is completely frozen, sometimes even with some snow on the ground, to make sure I am not compacting any soil. I only field mow what is absolutely necessary and keep the deck as high as reasonably possible to protect pollinator habitat.
Often, the work I do in wet meadows isn’t just invasive species management, it is maintenance of aggressive native plants as well. We have one wet meadow near our Wildlife Pond area that is completely full of willow (Salix spp.). The willow is great for pollinators, but it takes up a huge area of the meadow very quickly. I typically try to mow portions of it out when possible to prevent a monoculture of willow and give other species a chance to spread in the newly disturbed habitat. Another quickly spreading native we get in the wet meadow is Clematis virginiana. It spreads rapidly and can engulf other plants in the area. We have a large swath of swamp rose (Rosa palustris) that frequently gets covered by the clematis. In order to make sure both can exist simultaneously, I mow the area of clematis to keep it from spreading too far onto other native species.
Since these meadows experience the least disturbance, they tend to show intermediate succession species more frequently than other meadow types. Woody and shrubby species such as red maple (Acer rubrum), steeple bush (Spiraea tomentosa), willow, and nannyberry (Viburnum lentago) are seen more frequently. Even though most of the other meadow types on the property contain early succession species, I let the wet meadows stay as intermediate succession habitat because it fits the management timeline suitable for maintaining invasive species (3-5 years). I will mow intermediate tree species like red maple and white pine (Pinus strobus) because they quickly take up a lot of space in the meadow. I leave the shrubby intermediate species because they don’t compete as aggressively for space with the wildflowers present like Joe-Pye-weed (Eutrochium spp.) and blue flag (Iris versicolor), and goldenrod (Solidago spp.) and they are important habitat for both birds and butterflies.
Image 12: Swamp rose, blue flag, and solidago present in one of our wet meadows in June.
Meadow management is a broad and very individual topic based on a multitude of factors from habitat type, overall management goals, and personal preference. At New England Botanic Garden, we aim to promote early successional habitat for native plants to educate our visitors on what a native wildflower meadow can look like with proper management. By highlighting native species and successional habitat, we hope that visitors can take what they’ve seen in the areas I manage and create similar areas at their home gardens, businesses, and other locations to better support native plants and wildlife.
Robert Graham
Robert Graham is the Land Steward at New England Botanic Garden at Tower Hill located in Boylston, MA. He has been with the organization since 2017 and is responsible for overseeing all formal groundskeeping as well as management of all naturalistic areas including meadows, woodlands, and wetlands. Robert earned his BS in Biology from Worcester State University where he focused on conservation biology and GIS. His professional interests include early successional habitats, native plant ecology, and sustainable land management. Robert played an instrumental role in New England Botanic Garden’s adoption of electric landscaping equipment, an important initiative that led to the organization being recognized as the first botanic garden in the nation to earn Green Zone certification from the American Green Zone Alliance.
