Increasingly, park and recreation agencies across the country are hearing from community members concerned about the use of pesticides and herbicides in their local parks. They want these products banned, particularly the use of Roundup, because studies have shown that some of these herbicides are “probably carcinogenic to humans.”

Glysophate, the active ingredient in Roundup, was introduced to the consumer market in the 1970s as a broad-spectrum herbicide. Its effectiveness at killing weeds and grass is unparalleled and, if applied correctly, makes the task of maintaining weed-free lawns, plant beds and agricultural fields much less labor intensive. In fact, Roundup is the most heavily applied weed killer in the history of chemical agriculture, according to the Environmental Working Group. However, a number of credible studies are documenting a possible link between glysophate and a number of severe health problems, including cancer, according to the World Health Organization. Public concern is reaching unprecedented levels about the safety of these pesticides and herbicides.

Parks & Recreation magazine recently sat down with Merrie Talley, PLA, LEED, principal of Talley Landscape Architects, Inc., to learn from her about a method she’s spent the past 10 years learning how to do and that she calls “regenerative land management” (RLM). Following is an excerpt of that conversation:

P&R: People across the country and around the world are calling for the removal of one of the most effective weed-killing products. What do you say to those who wonder what they would use instead?

Merrie Talley: I have two answers to that: First, it really puts the onus on us as [landscape] designers to think in terms of what kind of plant communities we can grow. That’s part of the reason to plant native species. They will thrive in the climate they developed in. We’ve had to over use weed killers and synthetic fertilizers when we try to plant exotic plants, because they’re not thriving, necessarily, in a non-native place or they take over and become invasives.

Finding plant communities that fit the landscape is one challenge and then there are many less unwelcome plants, called weeds, to manage.

The next challenge is educating the public on what is a real living landscape. We have come to determine that a perfect bed is one where you never see the plant material look scruffy or go to seed, because we have developed a cultural expectation that it must look perfect year-round. That’s the reaction we receive when we use native grasses and wildflowers. We get a joyous clamoring from the public as soon as the big blooms start and a disgruntled one as it fades — ‘It looks messy, please mow right now.’ The normal life cycle of plants is that they mature, bloom beautifully and then those blooms turn to seed, so they can drop seeds and grow as wildflowers the next year. We get a lot of impatience in public spaces if we allow plant material to show us their life cycle, and it takes education, via signage, newsletters and public speaking, to counter this.

It is important to tell clients/community members what to expect. At certain times your landscape may not look perfect, but we’re waiting on the seeds to dry and fall to the ground, so we’ll have a beautiful wildflower area again next year. We do a lot of interpretive signs about the pollinators they will see and the life cycle of the plants. Our pollinators are wasps and bees and butterflies. We try to design habitat islands and say, ‘This area is reserved for our wildlife friends,’ or something like that. And, if there’s [a body of] water, we put them out on an island, so they can be isolated away from the public but still provide habitat and value and beauty.

Then, it’s finding the right plants, and educating the public about what to expect. This includes education about our turfgrass. For example, we often overseed in winter with clovers (legumes that fix nitrogen nodules in the soil). As they die in the warmer weather, they leave the nitrogen behind for the summer grasses. We always have to write a couple of articles explaining this or post in the local news letters where [our company] is working on a project, to let the community know we’re creating a meadow, not a monoculture. So, when we welcome these other plants (a diverse palette) that will join in with the turfgrasses, you’ll start to see all this insect life and life in the soil, and people feel the energy from it.

P&R: You’ve designed some award-winning parks that have been billed as ‘chemical- free’ parks. So, what is the definition of regenerative land management and what has been your experience in designing completely herbicide and pesticide-free parks? How do you go about accomplishing that?

Talley: We regenerate land by having more plants…there should be something green on that site at all times. Mama Nature does not like bare ground! That’s why having a mixture of evergreen and deciduous is important. We’re dealing with complex systems, and we need to learn how to take the next step, from ‘Now, we’ve done no harm,’ to regenerating, or think, ‘How are we helping this park’s soil become healthy and creating a cycle that helps it get healthier and better?’

In a regenerative system, all parts create the whole — Everything is welcome: insects, critters and people. In life, diversity is critical, good and important, and it’s the same in the plant community. It’s the same in the soil community. We have to get away from (1) these monocultures and exotics and (2) our cultural practices of mowing too low. We also need to reframe from ripping up swaths of ground on a routine basis to replant annually to meet that picture-perfect cultural expectation, when we could manage the progression of plants that occur as the landscape matures.

To me, regenerative is the way we’ve learned to put minerals down [into the soil], a sub-layer, when we first build a new park. Then we’re coming in and redistributing any existing topsoil (seedbank), then inoculating with a liquid biological extract (LBE). Compost tea is good, but LBE is more than compost tea. We’re trying to set up living communities that have diversity enough in their biological makeup that we’ve got a full spectrum of microbes — the ones that will eat and take organic matter down into the soil for the plants as they go through their life cycle and the ones that eat others to provide nutrition. When they excrete and secrete, they are putting out calcium, magnesium and other things that plants need. We also actively incorporate mycorrhizal fungi, because the fungi is an important aspect of the communication between the microbes and the plant root. And, we are also changing our cultural practices. For example, encourage park departments not to mow their grass down really low. They think by doing so, it kills the weeds, but the weeds are stronger than the turf, so they pop up faster. We recommend cutting the grass higher because your roots become deeper and stronger relative to the top growth. They can support the plants, hold more moisture and survive stressful events, such as drought and flooding in a living system. Then it all comes back to photosynthesis, the key to life. We sequester carbon and transfer nutrients to the soil via photosynthesis if the biology is there to synthesize it.

I now look at weeds differently. This has only been a decade of learning for me…an oversimplified example is learning that when I see certain kinds of asters, my calcium isn’t available to the plants. They’re an indicator of this lack of calcium, they have sent roots down and pulled up (mined) calcium and when they die, they leave that behind. So, I think, “OK, in our mineral mix that we’re going to put out this fall, we need to add that. Learning to read all of what a site is saying will take me a lifetime, but many farmers, scientists and authors have left texts for us. This is old knowledge re-applied.

So, we need to start thinking about our parks as places where every aspect works well with the whole life cycle of everything. Regenerative land management is about managing our landscapes to thrive. It’s thinking about parks holistically as nourishing spaces for ALL and how to set these systems up to nourish themselves and the life that teems within over time.

We regenerate land by having more plants…there should be something green on that site at all times. That’s why having a mixture of evergreen and deciduous is important. We’re dealing with complex systems, and we need to learn how to take the next step of, ‘Now, we've done no harm, how are we regenerating, or--how are we helping this park become healthy and creating a cycle that helps it get healthier and better and healthy?

We’re also insect-phobic in our worlds, or I find that. So, one of the things that’s going to be important in our parks, and again, educating people, is this need or the message of, ‘Everything is welcome: insects, critters and people.’ In life, diversity is critical, good and important, and it’s the same in the plant community. It’s the same in the soil community. We have to get away from (1) these monocultures and exotics and (2) our cultural practices of mowing and managing and not ripping up swaths and leaving them to dry out.

Many parks I know come in and occasionally change out their turf. Instead, it’s a slower process to figure out: ‘Okay, I’ve got a bunch of dollarweed in here. Why? Because it’s too wet. I’m going to need to manage this irrigation a little better because we’re putting too much water out.’ Then I’m going to make sure that my turf is healthy by what I’m putting on it — it needs a little more bacterial-based compost than fungal, because fungal is more in your woods, in your reforestation zones, and bacteria is more grasslands. So, it’s learning how to manage that…if you don’t have living soil and you don’t have microbes in your soil, you can put fertilizer out all day. It’s not doing any harm, but it’s not benefiting. Doing no harm is important, but then learning ways to manage and nourish beyond that is, to me, more the definition of regenerative.

So, we need to start thinking about our parks as places natives works well with the whole life cycle of it versus introduced plant life that then can quickly get out of balance because it didn't develop in this region. That doesn’t mean that sometimes things can’t be naturalized. I'm not saying we go in and wipe out anything that’s not native by any means. But, it’s about managing our landscapes and thinking about parks holistically and as nourishing spaces for ourselves, and how to set these systems up to nourish themselves over time.

We regenerate land by having more plants…there should be something green on that site at all times. That’s why having a mixture of evergreen and deciduous is important. We’re dealing with complex systems, and we need to learn how to take the next step from ‘Now, we've done no harm, how are we regenerating, or--how are we helping this park become healthy and creating a cycle that helps it get healthier and better over time?

We’re also insect-phobic in our culture, or I often encounter this. So, one of the things that’s going to be important in our parks, and again, educating people, is this need or the message of, ‘Every specie, everything is welcome: insects, critters and people.’ In life, diversity is critical, beneficial and important, and it’s the same in the plant community. It’s the same in the soil community. We have to get away from (1) these monocultures and exotics and (2) our cultural practices of mowing too short and managing by ripping up swaths of land and leaving them to dry out.

Many parks I am familiar with occasionally change out all of their turf. In addition to the great expense, it is really detrimental to the long-term benefits of a mature turf with deeper roots and working biology. Instead, in a natural system, it’s a slower process to figure out: ‘Okay, I’ve got a bunch of dollarweed in here. Why? Because it’s too wet. In this particular area. I’m going to need to manage this irrigation a little better because we’re putting too much water out.’ There may be a grading issue to resolve. Then I’m going to make sure that my turf is healthy by what I’m putting on it — it needs a little more bacterial-based compost than fungal, because fungal is more in your woods, in your reforestation zones, and bacteria is more prevalent in grasslands. So, it’s learning how to manage that…if you don’t have living soil and you don’t have microbes in your soil, you can put fertilizer out all day. It’s not doing any harm, but it’s not beneficial. Doing no harm is important, but learning ways to manage and nourish beyond that is, to me, more the definition of regenerative.

So, we need to start thinking about our parks as places where native plants work well with the whole life cycle versus introduced plant life that can quickly get out of balance because it didn't develop in this region. That doesn’t mean that sometimes plant materials can’t be naturalized. I'm not saying we go in and wipe out anything that’s not native by any means. But, it’s about managing our landscapes and thinking about parks holistically and as nourishing spaces for ourselves, and how to set these systems up to nourish themselves over time.

Let me be clear, on parks that are heavily used, we are not going to ever get away from having to add minerals and re-inoculate or augment the biology. Our parks never get rest. So, for example, I do intensive grazing on my own farm, which is divided up in parcels so that all my cattle are on one parcel for a week to 10 days and then they move to the next and each place only gets grazed two maybe three times a year. We can't do that easily in our parks. Therefore, regenerative, in that case, is setting up a system that will still require input but much less than we had before. By managing it, there may be times that we close [all experience] in the park for the resting of one area – for example, playing fields or a dog park area. In many cities, that wouldn't be practical, but because the use is so abnormally heavy year-round, then we’re still going to have to have inputs. We’re still going to have to mineralize and do things to help that land keep friable and building organic matter.

On our park projects, we soil test twice a year and the addition of organic matter is informative. We have designed projects using only indigenous soils that are mineralized and inoculated once they are built. On one project, starting with the worst subsoils, it took us four years, but we went from zero percent measurable organic material to 3½ percent. Now, I haven’t done this year’s testing, but we test every year to make sure the organic matter is increasing. We know that you need to get to a level of about 4 percent organic matter for sustaining your soil health. Beyond that is great. Then you’re sequestering more carbon. The NRCS [Natural Resources Conservation Services] estimates that for ‘each 1 percent increase in soil organic matter helps soil hold 16,000 - 20,000 gallons more water per acre.’. If you can get to 4 percent, think about it, you’re holding up to 80,000 gallons of water in your soil for dry times.

Ultimately, it’s your organic matter that you build up, and in Cows Save the Planet: And Other Improbable Ways of Restoring Soil to Heal the Earth, the author, Judith D. Schwartz, likens this to the difference between a dry sponge and a moist sponge. If your sponge completely dries out on your sink, and you try to wet it, it takes a good deal to re-wet it. But, if you take a moist sponge and wipe it across a spill, it absorbs it right up. So, my paraphrase of what she saying is what we’ve done is turned our surface, through the use of these chemicals and killing off the microbes (no organic matter), into a dry sponge. So, here we have 12 inches of rain and a dry sponge and it runs off, but when you have organic matter in your soil, it’s holding moisture and you have in effect a moist sponge. So again, first organic inputs help, you’re not killing any more, but then you must make sure you’ve inoculated and put back the mycorrhizal fungi, the microbes, the bacteria – the full spectrum of living soil.

We all are full of bacteria: beneficial and pathogens. When you’re in balance, you’ve got lots more beneficials than you’ve got pathogens. One of the ways I came on to this path [of RLM] was learning that when you get cancer, or you get weeds in your lawn or you get fungus, what’s happened is, we’ve beaten the beneficial bacteria back, through disease or lack of nutrient dense food. When the level of beneficial microbes is down low enough or out of balance, the pathogens with a very different life cycle jump at the opportunity to flourish. Beneficial bacteria have a more slow, rhythmic life cycle. Pathogens get a window and they grow fast and have a short lifespan. They go, ‘Hey guys, the guard’s not at the door,’ and they jump up and grow really fast and then you have to get them back in balance. People hear bacteria and they go, ‘Argh,’ but they have to understand that all the parts that Mother Nature puts out there have a purpose. It’s just balance. So, maybe, regenerative is more about balance.

My experience in designing [award-winning projects] is that I had to do education first about why to do [RLM] and the importance of it. My most well-known project is Mandolin Gardens, a project within Municipal Utility District No. 230, where we first completed a park overlay onto an 11-acre detention area whose primary function had to remain as flood protection for the community. We didn’t quite understand [RLM] but understood that it would be valuable if we didn’t have toxins in public parks and the need for sustaining steep slopes that were part of the method of actually increasing their detention volume. The Board supported our recommendations to go chemical free in concept and financially. We still manage the maintenance contracts on their parks and we have completed four of five phases of their masterplan since the initial project.

On four different projects, they support [RLM] by having me do the oversight. I’m what some would call the ‘gatekeeper,’ making sure things are done properly, and they don’t bring chemicals back when there’s a hard thing to solve. Early in our project our turf had a beautiful purple sheen. We found our potassium levels to be out of balance and with the addition of a mineral mixture, brought it back in balance to a nice green hue!

Looking holistically, two years ago we had an area where all the iris was lost in the stream bed. Well, it turns out, we had a huge infestation of nutria. They came from South America, where Jaguars and other things would prey on them. They have no predators here, and they do very bad structural damage by burrowing into your [bayou] side slopes. They have caused multi-million dollars of damage to the coastline, from Florida all around the South. Now, they’re found in every state, and they’re totally out of control – a literal invasive species. We trap and remove them to maintain a balance in the ecosystem we have reconstructed. No single species can be poisoned without there being possible dangers for others in the food chain.

So, balance is probably the Primary key to Regenerative (RLM). But, first and foremost is the leadership with understanding and support from a client or a directing board that understands its value. The board, then, has gotten the support of the community because, as research shows, public green space always brings economic value to the community. Texas A&M’s Dr. John Crompton did tons of research and four books about how green space always is the core of economic value to a community. If we’re regenerating our land and keeping it healthy and energized, it is a magnet for development of the residential or commercial space adjacent to green spaces.

P&R: What’s the goal of a chemical-free park and what are the most important takeaways you want people to know?

Talley: The goal is healthy places for our people and, thus, the planet, and regenerative is carbon placing. If we’re building carbon, then we’re taking it out of the atmosphere through photosynthesis and putting it in the land. When you hear, ‘reducing your carbon footprint,’ everybody goes, ‘Oh, yeah. Oh, yeah.’ That only happens through photosynthesis. There is no air filter that pulls carbon and place it in a little container. That’s not how we reduce our carbon footprint. The only way is to move it, and the only vehicle to move it is plants via photosynthesis. If we cut our forest down and we have only big lawns and no trees, we don't get very much exchange from the grass. Yes, you get some, but it’s based on square inches of photosynthesis. A tree, with all those leaves, provides a lot of photosynthesis. Doesn’t compare to the turf, but we need all of it. When you start thinking that the only way we could get the carbon out of the air and the only way we get oxygen is through the plants, it’s unconscionable that we’re taking down so much forest. We’re literally removing lungs from our planet.

Trees are breathing a lot and taking lots of carbon out and providing us with many things and harboring birds and insects that are beneficial. So, it’s our tree ordinances, again education, education, education -- reminding people that if there is one building block we need to think about, it’s photosynthesis. It is about how our plants are saving us, nourishing us, saving the planet. And our parks, we hope, protect the plants, and our developments, we've got to press more for our developments, if they've got existing trees, to be creative enough to work around a grove of trees and still get development.

It has been considered standard practice for a long time in landscape specifications to sterilize the soil using chemicals to kill all the living things. We thought we wanted sterile soil, and we just put synthetic chemical there and fertilizers. Now, I say, “No, no,” and people will go, ‘Well there’s weeds there.’ Ok, when our grass is healthy and we’re growing it, right, Mother Nature won’t need weeds. I do a lot of detention basins where I do what I call a “park overlay.” When I do that, the first thing that happens, if we haven’t imported soils and we haven’t killed everything, is these big gnarly weeds that I used to despise (as in didn’t understand their value), like goose grasses and crabgrasses, come in. The woman who helps with my soil nutrition came out and said, ‘Let’s dig this up and see what is happening.’ Now, I’m planting grass on a 3–1 side slope. In a week or two, these first responders (many would call weeds) come up and we’re going, ‘oh my gosh,’ and they cover it. You dig down and there’s a big taproot. ‘Why do you suppose that is?’ she asks me. Well, if I was trying to put erosion control or hold this slope, I would pack it with jute mesh and put pegs and things. These plants are serving to hold my slopes. She said, ‘Let’s give this some time. We’ve built a community that will support your grasses,’ and, sure enough, it takes very little time when I’m just not seeing those weeds, but the grasses are coming in. Well, Mother Nature abhors a vacuum. She wants her skin — the earth — covered, so she sent what I now call ‘first responders,’ and she pegged that soil, and she held that slope in place. Just like in a disaster, we will send the fire and all those rescue people, but they don’t stay all the time. They come in, they respond to the immediate need and then, as the systems get re-established, the first responders are no longer needed and they are replaced. They go to the next disaster. Mother Nature sends the right tools at the right time. We simply have to be knowledgeable enough to interpret and learn.

Now, I’m not as knowledgeable in these formulas, so I use a company – Sustainable Growth of Texas – and that is their business. I have learned that the unwanted plants (weeds) are an indicator of some imbalance. They’re telling us what’s going on in our soil. When we remedy that, they are no longer needed and they don’t come back. Over the long term, we are managing our turf, our inputs into the soil and the mixes that we’re applying to establish the landscape we desire – not reacting to what comes in the interim. Mother Nature sent them because there was a need and we establish a regenerative system; their jobs are replaced, and we function well inviting ALL to partake of the bounty within the landscape.

Sonia Myrick is NRPA’s Executive Editor of Parks & Recreation magazine and Richard J. Dolesh is NRPA’s Vice President of Strategic Initiatives.