Ecological horticulture is one of the most important methodologies that gardeners can adopt to combat the loss of biodiversity, but the term is still unfamiliar to many. To explain ecological horticulture and how to practice it, my guest this week is self-described “ecologically obsessed” director of horticulture at Brooklyn Bridge Park, Rebecca McMackin.
Rebecca is the director of horticulture at Brooklyn Bridge Park, an 85-acre public park on the East River. She is someone who not only gets the significance of ecological horticulture and its evolving nature but is able to put all of this into practice in a very profound and public way.
Rebecca grew up on an old, small farm in Connecticut. Her mother was a professional gardener and actually went into labor with Rebecca while in a garden. Despite all of her exposure to gardening and agriculture, Rebecca never considered horticulture as a viable career. “I thought gardening was just for fun,” she says. But after years of traveling and working in fashion, political science, arts and literary journals, she moved to British Columbia to pursue a degree in biology. “I studied freshwater ecology, and I discovered the natural world in a whole new way,” she recalls. “And I fell in love with it.”
Though Rebecca loved the material and learned how to critically access and interpret scientific research, she became disenchanted with academia. “It was brutal,” she says. “I literally lost my long-range vision from staring at a computer screen. And so when I finished a master’s degree, when I was 30, I still didn’t know what to do.” She took a break and lived in a cabin on her father’s property. It was then that she began teaching yoga and gardening at a native plant nursery. Though she wasn’t planning for the future or a career, she found her calling.
Rebecca says gardening was beautiful and fascinating. “There was so much that hadn’t been studied that needed to be researched, but no one was asking me to do statistics.”
She moved to Brooklyn to become a gardener for the New York City Parks Department. She gardened at Coney Island and Washington Square Park, the latter of which is one of the busiest parks in the entire city. She says that means dealing with tourists, working with unhoused folks and yelling at people taking photos in the middle of the tulips display, including celebrities.
She continued her studies at Columbia University and earned a degree in landscape design. Between her education and her experience, she was chosen to manage Brooklyn Bridge Park about 10 years ago. It was just a tiny nascent project then but has grown exponentially.
I found my conversation with Rebecca to be filled with incredible nuggets of wisdom, thought-provoking ideas, and inspiration that each of us can play a vital role in refining what we do in our own gardens and landscapes to promote healthier ecological systems that are now more important than ever. There was much to discuss with Rebecca, so much so that our conversation was split into two parts. Part two will follow next week.
Understanding Ecological Horticulture
Over the course of 230 episodes of “The joegardener Show,” I’ve picked up a lot of information and valuable ideas that have changed the way that I think and act in my own gardening practices. As times are changing, familiar terms that we’ve heard for years are taking a deeper meaning when preceded by key adjectives. For example, the term “regenerative agriculture” has a much deeper meaning than “agriculture.” Likewise, looking beyond horticulture, where plants are often treated as more of a commodity, there is “ecological horticulture,” which is based on the understanding that living organisms are in community with other living organisms.
Ecological horticulture examines how interactions between living things shape and make our gardens. When gardeners are attentive to those interactions and adapt to observations, our gardens are living, thriving, moving ecological systems.
With the help of advocates like Rebecca, we’re learning much more about how those systems and the members of those communities ebb and flow together, and it’s changing how we care for our gardens and landscapes, public parks, and beyond. We’re discovering our role in all of this may mean doing less, getting out of the way and embracing the concept of natural aesthetics. Restraint is not neglect, not everything has to be green and tidy all the time, and form and beauty can still exist while allowing those systems time to play out as nature intended.
Whether hobby gardeners or professional horticulturists, we’re in the process of relearning how and when we do what we do and discovering and developing new practices that go beyond just inviting in more wildlife. We’re honoring those spaces that support the full lifecycle of that wildlife.
Ecological horticulture is more than the classical organic gardening movement. It looks beyond the flowers and the plants. “It prioritizes the dynamics among the plants and the wildlife and the soil microorganisms and the people critically,” Rebecca says. “People are a big part of this process as well. It’s about these relationships among all of the various organisms, and we consider the garden as a system that changes and adapts to conditions over time.”
Instead of expecting trees and plants to be exactly where you left them years later, which is the case with traditional horticulture, ecological horticulture looks at gardens as changing, adapting systems that are constantly in flux. It’s how gardens can deal with climate change.
Planting the plants is just the first part of the process. Gardeners like Rebecca who practice ecological horticulture observe the species of wildlife that visit the garden and how those species use the garden throughout their lives. Through research and experimentation, gardening practices are altered to better support that wildlife.
Native plants provide food for herbivores but they do so much more. They provide nesting sites, nesting materials, overwintering habitat and other necessities for insects and birds.
Creating a beautiful garden and creating a garden that supports diverse wildlife are not mutually exclusive ideas. Take, for instance, Brooklyn Bridge Park. The millions of visitors annually just see a beautiful park while few know of the underlying mission.
The Ecologically Sensitive Brooklyn Bridge Park
Brooklyn Bridge Park was built on shipping piers that jut out over the East River. The piers were constructed in the 1950s and ’60s, but they became obsolete with a couple of decades. Cargo ships stopped delivering there in the early 1980s. When redevelopment was proposed for the site, the community asked that it become a public-use space. It took 30 years, but in 2008 construction became on Brooklyn Bridge Park, and the first section opened in 2010. The last section of the park is scheduled to be completed this fall.
The park has more than 3,500 young trees and even more saplings growing on what is essentially a concrete slab. Landscape architecture firm Michael Van Valkenburgh Associates, which specializes in post-industrial design and reclaiming old landscapes for green space and public enjoyment, was responsible for the amazing and innovative design. The design includes grassy berms and hillsides, something that’s otherwise not seen in flat New York City, and a number of ecosystems, such as salt marshes, grasslands, forest habitats and freshwater streams. The streams have the bonus of filtering rainwater that is then reused as irrigation in the park.
“It’s this really ecologically intentional project where it was always designed to be organic, always designed to serve as habitat for wildlife,” Rebecca says. “And we’ve really been fortunate enough to take that and then have this solid decade of research and observation and experimentation into how we can manage the land and develop practices that encourage wildlife in a very real way that we can then turn around to the public and share what we’ve learned.”
Not only is it a place to play soccer, but Brooklyn Bridge Park is also a place to get back in tune with the rhythms of the planet and learn about them, she says.
The Brooklyn Bridge Park horticulture team are the stewards of this project. “We take the ecological part of this mission really seriously,” Rebecca says. “We consider it our job to figure out how to incorporate quality wildlife habitat into cities.”
Many bird species won’t nest in areas that are cut back every year, Rebecca notes. They need space from us, so there are parts of Brooklyn Bridge Park that staff and the public stay out of. When their resident birder, Heather Wolf, notices that song sparrows, for instance, are making nesting calls, the staff will refrain from visiting the area of the park where the sparrows were heard.
Species that they never thought the park would be able to support have returned. The strategies that they have developed themselves or borrowed from others have been quite successful and can be applied all over. This is significant considering that 45% of arthropods have been lost in the last 35 years and that North America has lost a quarter of its birds.
We can often get the sense that we can’t make real change in these big, complicated issues, Rebecca says, but with gardening and ecological horticulture, we can witness the return of the butterflies first hand.
An Exciting Time to Be in Horticulture
The availability of native plants in the marketplace is a fairly recent development and a major change in horticulture. Gardeners who want to plant natives have more options than ever before. The amount of research that is now readily available on the internet is also making it easier for gardeners to succeed in raising native plants and attracting monarch butterflies. Apps such as iNaturalist make it easy to identify plants.
Rebecca gives a great example of what can be accomplished by using all of the tools at hand. A staff naturalist identified the sooty wing butterfly as a visitor to Brooklyn Bridge Park. Rebecca then looked it up on a great resource, ButterfliesAndMoths.org, and learned that its host plant is lamb’s quarters, which is considered a weed. To support this butterfly during its caterpillar phase, the park’s staff stopped pulling out all of the lamb’s quarters (Chenopodium album). In spots where it would be out of sight, lamb’s quarters is allowed to grow to provide food to the caterpillars.
Additionally, if any of lamb’s quarters plants are being weeded out, they are scanned for eggs first. If eggs are found, they are brought to the lab to hatch, pupate and be released back into the park.
Another park visitor is the pearl crescent butterfly. One of its host plants is the smooth aster. In the caterpillar stage, it overwinters at the base of the aster. With this knowledge, Brooklyn Bridge Park gardeners make sure that when they cut back the asters in April that they will not disturb the caterpillars. They also refrain from raking out the garden, which also affects overwintering insects.
The layer of organic material that is between the leaf litter and the uppermost soil mineral horizon is known as the duff layer. If the duff layer and the litter layer are removed to keep things today, many overwintering insects will have no habitat.
Many insects survive winter in the subnivean zone — the area between the surface of the ground and the bottom of the snowpack. The snow creates a thermal layer like a down comforter, and the subnivean layer stays warmer than the air above and never freezes. If leaves, stems and twigs are removed for the sake of tidying up, there is no place in the subnivean layer for insects to live over the winter.
The duff layer and the subnivean zone are vital to the bumblebee, a gentle and important pollinator. To refrain from harming bumblebees and other insects, the Brooklyn Bridge Park team has changed its approach to maintaining bunchgrasses. Instead of cutting bunchgrasses down to the ground and raking out the garden, only the top of the grass is cut to prevent rotting and the ground is left alone.
Learning From Plants
Rebecca adheres to the words of Robin Wall Kimmerer, the botanist and author who teaches that gardeners should learn not only about plants but from plants. Direct relationships and observations are how gardeners learn what plants need and what services they provide to wildlife. It is an indigenous perspective on ecology that is now gaining recognition as traditional European perspectives on what a garden should look like are deprioritized, Rebecca says.
The reality is that the biggest disturbance in our garden is often the well-meaning gardener, according to Rebecca. She points to a study done in St. Louis a number of years ago. The researchers found that pollinators were more abundant in neighborhoods with less income, and less abundant in high-income neighborhoods. The difference is that in high-income neighborhoods the resident hired landscapers and gardeners who routinely sprayed pesticides or removed insect habitat.
Trying to be in control all the time is a futile endeavor, Rebecca says. It’s actually when we stop micromanaging that gardens perform better and become more useful to wildlife.
I hope you learned something from my conversation with Rebecca McMackin. If you haven’t listened yet, you can do so now by clicking the Play button on the green bar near the top of this post.
Do you practice ecological horticulture? Let us know in the comments below.
Links & Resources
Some product links in this guide are affiliate links. See full disclosure below.
joegardener Online Gardening Academy™: Popular courses on gardening fundamentals; managing pests, diseases & weeds; seed starting and more.
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joegardener Online Gardening Academy Perfect Soil Recipe Master Class: Learn how to create the perfect soil environment for thriving plants.
joegardener Online Gardening Academy Beginning Gardener Fundamentals: Essential principles to know to create a thriving garden.
joegardener Online Gardening Academy Growing Epic Tomatoes: Tomato expert Craig LeHoullier joins me in leading this course on how to grow healthier, productive tomato plants and how to overcome tomato-growing challenges.
Disclosure: Some product links in this guide are affiliate links, which means we get a commission if you purchase. However, none of the prices of these resources have been increased to compensate us, and compensation is not an influencing factor on their inclusion here. The selection of all items featured in this post and podcast were based solely on merit and in no way influenced by any affiliate or financial incentive, or contractual relationship. At the time of this writing, Joe Lamp’l has professional relationships with the following companies who may have products included in this post and podcast: Rain Bird, Corona Tools, Milorganite, Soil3, Exmark, Greenhouse Megastore, High Mowing Organic Seeds, Territorial Seed Company, Wild Alaskan Seafood Box and TerraThrive. These companies are either Brand Partners of joegardener.com and/or advertise on our website. However, we receive no additional compensation from the sales or promotion of their product through this guide. The inclusion of any products mentioned within this post is entirely independent and exclusive of any relationship.