Among the towering skyscrapers, bright lights, and bustling crowds of New York City, a flower blooms. Just as its red petals unfurl, it welcomes its first visitor. A ruby-throated hummingbird flits over—its wings emitting a low buzz. As a police car flies down the street, alarm blaring, the bird flies closer, sipping a few drops of nectar. Its sudden appearance draws the attention of a nearby woman, who watches in amazement as the bird zips from one flower to another, making quick work of a tower of red blooms. Nearby, as a mail carrier opens a blue mailbox, a stray breeze catches her attention. Behind her, a garden, standing out on the corner of a busy block, is an unexpected safe haven. A milkweed flower sways in the wind, visited by a couple of brightly colored butterflies. The sight brings a brief moment of bliss. Just down the street, a small traffic jam leads to an eruption of horns. A summer grape winds up a trellis, its green fruits slowly turning purple. In the center, a bench rests beneath a small dogwood tree. Beside it, a sign reads:
“Native Garden”.
New York City may be known as the concrete jungle, but more than 1,300 native plant species thrive in its 5 boroughs. Native gardens support local species, and may even require less maintenance, benefiting both gardeners and surrounding ecosystems. But what are native plants, and how do they differ from invasive species?
What Are Native Plants?
A native garden consists of plants that have historically grown naturally in a region and have adapted to its characteristics. In the United States, native plants are those that have been present on the land before European colonization. Native plants have essential relationships with surrounding organisms, such as native birds and insects. Milkweeds, for example, are plants that support a wide variety of pollinators, including moths, wasps, bees, hummingbirds, and butterflies. Notably, milkweed plants are essential to the survival of monarch butterflies, serving as a food source for both caterpillars and adult butterflies. Additionally, large milkweed bugs rely on the plant almost exclusively, consuming leaf and stem matter, seeds, and even aphids! Butterfly milkweeds also support many local birds, including wrens, woodpeckers, vireos, thrushes, and orioles.
Other native plants can have a complex relationship with both the biotic and abiotic components of their ecosystems. For example, smooth cordgrass, a plant native to the U.S. Gulf and Atlantic coasts that grows in low-elevation areas of salt marshes, aids in keeping soil compact and stable and serves as a source of food and shelter for a variety of organisms, including greater snow geese and muskrats, respectively. Smooth cordgrass has developed a unique mutualistic relationship with ribbed mussels, another species that is native to the Atlantic coast. While smooth cordgrass provides protection for ribbed mussels against the heat (and desiccation), the mussels also help these grasses, transfering nitrogen in the water to the sediment for use by the plants. Without these grasses, mussel beds could become contributors of more nutrients, which could promote marsh degradation. Native plants help keep ecosystems balanced and healthy.
What's the Deal with Invasive Species?
While native plants offer many benefits to local ecosystems, invasive species threaten the delicate balance keeping these systems healthy. Invasive species are a type of non-native species. Non-native species have been introduced to an area where they were not growing naturally/historically. Unlike other non-native species, invasive species pose a significant threat to both the environment and humans. Some invasive species are intentionally introduced. Water chestnuts, for example, were brought to the United States in the late 1800s, including specimens brought to the Cambridge botanical garden in 1877. These plants form dense mats in bodies of water, shade out other plants, and make movement in the water difficult. Water chestnuts threaten local ecosystems by outcompeting native plants, depleting key food sources for local fish, and contributing to the creation of dead zones, areas in bodies of water with low oxygen levels. Without food or oxygen, fish populations may undergo massive die-offs. Eradicating water chestnuts from an infested body of water is often an arduous and time-consuming task. The New York State Department of Environmental Conservation (NYS DEC) suggests that the area should be monitored for 12 years following hand-removal to ensure there are no seeds left behind.
Invasive plants can have widespread impacts. Non-native Phragmites australis are notoriously destructive. These reeds grow rampantly in wetlands, replacing native species over large swaths of land. Phragmites can alter the structure of a habitat, impacting not only community composition, but also water salinity and susceptibility to fire. These plants can also spread quickly through urban areas, populating ditches along highways and roads.
Another set of plants that have become invasive in New York are the common and Japanese barberry. Initially, common barberry was introduced by European colonists, but quickly became invasive, facilitating the spread of black stem rust. This disease, which is caused by a fungus (Puccinia graminis), can infect wheat and other grains, as well as native Mahonia plants such as the holly-leaved barberry. Japanese barberry was introduced in 1875 as an ornamental plant. This species has also experienced explosive growth, and it is also considered invasive. Although it is rust resistant, this barberry can hybridize with common barberry, producing offspring capable of carrying black stem rust.
Another notable invasive species that can be found throughout NYC is the tree of heaven. Known for its foul odor, this tree poses a direct threat to native species by releasing toxic chemicals that limit the growth of other plants. The tree of heaven also hosts the spotted lanternfly, another invasive species. This species also has a complex root system, making control extremely difficult. Even if a tree is cut down, new trees may sprout up from both the roots and stump. Invasive plants can have wide-ranging effects on native plants.
Invasive plants also do not provide the necessary support for native species. In a 2018 paper, researchers from the University of Delaware and the Smithsonian Conservation Biology Institute discovered that increasing numbers of non-native plants led to lower arthropod abundances, forcing Carolina chickadees to find other food sources. On the other hand, native plants better support native species, providing sufficient food and shelter for the many animals that call New York home.
What Can We Do?
Although invasive plant species can be beautiful, native plants better support native and migratory species. However, it might seem a bit difficult to figure out which plants are native to New York, and how to establish them in the city. There are many resources available to assist prospective gardeners in designing their own native garden. For example, the National Audubon Society has a tool that helps users search for native plants using their zip code. The National Wildlife Federation also has a native plant finder, which can be useful for determining which plants they may want to grow.
There are so many ways to start on your journey to native gardening! Roof-top gardens and community gardens can be great spaces for native plants, and residents can work together to maintain a beautiful, sustainable garden. Window planters and balcony container gardens can also be very useful in areas with little to no available outdoor space. This not only helps brighten up window and balcony views, but also supports local wildlife on the go!
There are many ways to get involved with native gardening. For example:
- Mary really loves aquatic and wetland plants, but isn't quite sure how to introduce them into her backyard. There are several resources that could be helpful, such as the DEC’s Guide To Water Gardening in New York State, which suggests a variety of native species that can be planted both in and around bodies of water. The guide also warns the reader of invasive species that should not be planted, such as water hyacinth, water thyme, and the aforementioned Phragmites australis. Mary could also read the list of native plants found in non-tidal freshwater wetlands from the Greenbelt Native Plant Center, which offers several options for wetland plantings based on soil pH. Mary could also reference online guides to create a water garden, including larger in-ground ponds that could support a variety of plants (and native wildlife!). She could also create a container water garden, which could support various plants despite its small size, or assemble several container gardens outside.
- She does not have a balcony, but her apartment does have a few windows. Ever since she saw a hummingbird at a nearby community garden, she's been curious about how to learn more. She could get involved by researching window plantings. The National Audubon Society notes that window boxes with native plants can both support birds and provide residents with an opportunity to see them. The Greenbelt Native Plant Center also provides a list of native plants that are helpful for birds. Stella could review this list and look for plants that might be suitable for window planting, such as cardinal flowers. She could also take a look at the National Audubon Society’s Native Plants Database. After deciding which species she would be interested in planting, Stella could then research window planters. There are several different options for window planters depending on window size and structure, but you could also build your own! However, because window collisions are a big issue for birds, she should also invest in window decals to ensure that any visitors stay safe. She could also get involved with her local community garden, where she could grow even more bird-friendly native plants.
- Jordan lives near a community garden, but isn’t sure how they can join, or how they can incorporate native plants. They could read through the NYC Parks guide to joining a GreenThumb community garden, found on the NYC Parks site. This guide provides resources for locating and connecting with local community gardens, including each garden’s contact information. Once Jordan identifies their local garden, they could also join a GreenThumb event at the garden, if any are being held. As a volunteer, Jordan would have a chance to familiarize themselves with the garden and its members. The NYC Parks site also provides a video playlist to help those interested in joining a garden, as well as a handbook for gardeners. Jordan should note that the gardeners as a whole determine the garden’s purpose, and that they may have to find specific native plants that fit this purpose. For example, if Jordan’s local community garden focuses on growing food, they could search for different edible plants, such as raspberry bushes or prickly pear cacti.
Ultimately, native gardening will not only give you the chance to see beautiful blooms, but also a wide variety of native and migratory species. A transition to native gardening can help us better support the species that are struggling the most.
Among the bright lights and bustling crowds, a tranquil moment unfolds: slowly, carefully, a window opens. Peering out from a warm room, a woman watches the pigeons dive between buildings. It’s far from the first time she’s seen them gather, smooth as synchronized divers, but the moment still leaves her in awe. As she waters a thriving bunch of lobelias, a movement in the corner of her eye catches her attention. In another window box, just a room away, a mourning dove tops off a small pile of sticks with a string of grass, watching as another begins to assemble the materials into a nest. Nestled between the wide leaves of her appropriately-named broad-leaf sedge, they settle down. It isn’t what she expected, but she’s thrilled nonetheless.
Elsewhere, a woman looks out over her small yard, appreciating the glimmer of the sun on her new pond. Lesser duckweeds grow in clumps, surrounded by the brilliant blooms of white water lilies. A few cattails grow tall, their leaves stretching up towards the sun. Suddenly, a visitor zips into the scene, landing gracefully on a lily pad. The pitch black wings and sleek, metallic blue body of an ebony jewelwing damselfly leave her dashing for her camera.
Between two office buildings, a community garden thrives, its beautiful blooms and bright leaves drawing the attention of passersby. Along a cast iron gate, a set of prickly pear cacti lounge in the sun, a proud gardener looking down on them with a smile. A few feet away, a small raspberry bush sways in the breeze, its vivid, juicy fruits drawing the attention of a pair of hungry cedar waxwings.
Native urban gardening can be an extremely worthwhile practice, bringing joy to gardeners and providing native species with a chance to thrive in the Big Apple.