Native Plants
- Definition of “Native Plant”
- List of New York City’s Native Plants
- Threats to Native Plants in New York City
- How Plants Become Rare
- How You Can Help Wildflowers
Definition of “Native Plant”
Jewelweed (Impatiens capensis), found in wet areas, is one of our most common native wildflowers.
A native plant is one that naturally occurs in a region without having been introduced from elsewhere by people. New York City natives include mosses, ferns and fern allies; grasses, sedges and rushes; forbs “wildflowers”*; trees, shrubs and woody vines. *(“Wildflowers” is in quotes because except for mosses, ferns & allies and conifers, all of the above are flowering plants, i.e., angiosperms).
Native plants are an integral part of our ecosystems, having evolved relationships with local insects, fungi, diseases, birds, mammals and other vegetation; the building blocks of our biodiversity. They are the wild, unplanted thread in the Big Apple’s biological tapestry, which has begun to fray. New York City has already lost more than 30% of its native plants. This trend continues today.
Native genotypes. Over millions of years, native plants have adapted to the climate, soils and environmental conditions of our locality. This site-specific evolution is reflected in their genetic makeup. Sculpted by nature, the plants found here have become perfectly suited to this place. The individual range of each plant extends beyond our political borders. Some species are found more to the south, with this being the northern part of their range. Others are more abundant to the north or Midwest.
Saltmarsh cordgrass (Spartina alterniflora) is the dominant species in salt marshes, like this one in Marine Park in Brooklyn.
A species is native throughout its range, and its range may cover many states. However, it has multiple genotypes, and these are regionally divergent, representing the breadth of differences within its range. These variations reflect the vagaries of chilling winters and scorching droughts and the timing of floral or fruit displays with the appearance of local pollinators and seed dispersers. For example, in the mid-1990s, salt marsh cordgrass (Spartina alterniflora)from Maryland was used to restore salt marshes in Staten Island. These foreign genotypes faired terribly, the Maryland plants were short, spindly and few-flowered. Local cordgrass seeds were then collected from healthy New York City salt marshes. Accustomed to urban stressors, our local genotypes flourished; the grasses were tall and lush with a profusion of flowers. Thus when discussing the installation and conservation of native plants, we mean local genotypes of native species.
“Every native species, however humble in appearance…has its place in the nation’s heritage. It is a masterpiece of evolution, an ancient, multifaceted entity that shares the land with us.”
- E.O. Wilson, myrmecologist and evolutionary biologist
List of New York City’s Native Plants
List is forthcoming
Threats to Native Plants in New York City
As the southern-most tip of New York State, Staten Island's south shore has many unique and rare plants. Unfortunately, development here is rampant.
Most people tend to think that dramatic, isolated incidents are responsible for loss of biodiversity. Flashy events like oil spills or forest fires garner headlines. While these are certainly detrimental, the loss of biodiversity in the New York City area is largely due to the ongoing destruction and degradation of habitat. Our natural areas are shrinking and deteriorating, with vast stretches struggling to support our biological riches. This pattern of habitat loss is alarming since it undermines efforts to conserve what remains of our biodiversity.
Habitat destruction through development. The biggest threat to our native plants and other biota is habitat destruction due to development. Given that so little land remains unbuilt, in the New York area, no open space is safe. Our forests of oak and hickory are traded for box stores and their concomitant parking lots. Public works projects bully their way through parklands. Our forests and fields are only valued when “improved” through human activity and the original greenery is gone.
Habitat degradation. Equally worrisome is habitat degradation. This is more insidious, less obvious than the above. Unbuilt parcels are not necessarily safe havens for biota. The corrosive factors at work here are of two scales:
1) Landscape scale (what humans do collectively) – Stressors such as air pollution, water pollution, soil contamination, erosion and siltation. These are the effects from new housing sites, where newly dug dirt piles wash into lower-lying wetlands, smothering the plants and animals that live there. Or from roadways that encourage the spread of invasive plants and degrade local air quality.
2) Human scale (what humans do individually) – Dogs roam off the leash and off the trail; all-terrain vehicles, motorbikes and mountain bikes tear up wildflowers, compact soils and carry invasive seeds; and arson burns plant seedlings and organic matter in soils. Our native wildflowers and ferns are particularly vulnerable to these disturbances.
Healthy forest in Inwood Hill Park in Manhattan with multi-tiered vegetative layers.
The face of loss. For example, dangleberry (Gaylussacia frondosa)is holding on by a thin twig in New York City. This shrub is a member of the heath family, with white, bell-shaped flowers in summer and edible blue berries in fall, much like its cousin, the blueberry. You will find this plant in the umbrage of oaks, growing in the acidic, nutrient-poor soils of undisturbed, pinelands-like forests. Four of its New York City populations are now gone, buried under acres of asphalt and concrete; only three remain. For one site, “population” is an optimistic term for the lone plant. In Long Pond Park in Staten Island, there is only one shrub. Here it inhabits an island carved out by mountain bike trails. Nothing grows in these tracks; the resultant bare mineral soil is desertification on a linear scale. Alienated from the rest of the forest and with no neighbors to produce viable seed, this particular plant is the last dangleberry in these woods. When it dies, this species will be removed from the park’s flora.
A healthy, functioning forest is as multi-tiered as a layer cake. The tallest trees form a canopy, under which shade-tolerant saplings and shrubs grow. Vines climb upward to secure light for themselves. On the forest floor, seedlings of woody plants intermingle with ferns, grasses and forbs. Contiguous canopy cover is punctured periodically by light gaps created by fallen trees. Enough of these natural openings allow shade-intolerant plants such as oaks, hickories, pines, sumacs, roses, asters and goldenrods to gain a foothold in new habitat. Migration allows plants to persist over the larger landscape when their present habitat is no longer hospitable. Aided by wind, water, or animals like birds, small mammals and ants, plants are recruited from neighboring sources into new sites, so that a small area may show a net loss or gain of species, but over the larger landscape the variety of vegetation is static.
Healthy forest in Alley Pond Park in Queens .
In a healthy forest, disturbance from humans is minimal. As expanses of woodland are carved into smaller pieces by surrounding development, they begin to show signs of stress. Siltation and erosion increases, and water quality decreases, degrading forest soils. Incoming plants are no longer native species from forest interiors but roadside weeds from marginal habitat. Struggling against the strain of newly introduced pollutants, indigenous flora succumb to disease and herbivory. Encroaching development limits pollinators and seed dispersers, rendering flora incapable of renewing their populations. As these die off, exotic species take their place.
While no native can combat the onslaught of ills described above, the greenery carpeting the forest floor is especially intolerant of such stressors. These grasses, sedges, ferns and forbs spread slowly & establish new populations infrequently. Such plants die off quickly in the face of siltation, dumping, mountain bikes and development. Mature trees, despite being focal (and rallying) points for people, are poor indicators of forest health, since they are the last to go. It is the herbaceous community that acts as the “canary in the coal mine”; through their disappearance they warn of poor ecosystem quality and further degradation yet to come.
American chestnut (Castanea dentata), decimated by chestnut blight fungal infection introduced to this country through the importation of exotic Japanese chestnuts by the horticultural trade.
Habitat degradation also affects:
WATER QUALITY/WETLANDS: Replacing forests and fields with buildings and roads increases the amount of land impenetrable to precipitation. This creates large volumes of runoff collecting motor oil and other pollutants en route to low-lying areas. The quality, volume and velocity of this water has a deleterious effect on our wetlands, home to many of the city’s most imperiled plants. See how siltation and pollution killed populations of the federally endangered swamp pink (Helonias bullata).
EXOTIC INVASIVES: New York, as a port city of active commerce, is a gateway for foreign invaders of all kinds.
Worms: Earthworms are not native to the northeastern U.S. These exotics, brought in from Europe and Asia, are mighty munchers, leaving destruction in their wake. They make our soils inhospitable to native plants. The presence of earthworms leads to precipitous drops in plant diversity.
Plants: Drosera’s Invasives page
Diseases: Importing exotic plants seems like an innocent pleasure, except that these introductions often carry foreign diseases. These pestilent hitchhikers, new to our indigenous flora, leave destruction in their wake. For example, it is likely that a nursery in Queens was responsible for the decimation of one of our most treasured trees, the American chestnut (Castanea dentata). A related species, Japanese chestnuts (Castanea crenata), were first imported into the U.S. in 1876 by S. B. Parsons of Flushing, NY. These exotic trees were widely distributed. In 1904 a rusty fungus was noticed on American chestnut trees in the Bronx Zoo. Within 50 years chestnut blight (Cryphonectria parasitica), that had been carried into this country on the Japanese chestnuts, had destroyed 9 million acres of American chestnut-dominated forests in the northeast. Learn more about chestnut trees and blight.
Insects: Packing materials and commercial products from overseas often carry hidden visitors. For example, the Asian longhorn beetle (Anoplophora glabripennis) immigrated to North America via wood packing material from China. The pests attack and eventually kill many of our tree species. Learn more.
Trillium decapitated by white-tailed deer.
White-tailed deer: Nature in New Jersey, southern Connecticut, eastern Pennsylvania and southern New York State is overwhelmed by white-tailed deer (Odocoileus virginianus). (New York City is largely deer free). Deer are a threat to local flora because they don’t eat exotic plants, instead preferentially devouring natives, especially our lovely spring wildflowers like trillium and trout lily. Deer destroy all indigenous flora from the forest floor up to 5 feet high. This area is called a browse line (see the damage). Lack of native vegetation also results in loss of other animals. For example, as deer densities rise, nesting songbirds become scarce. Here is photographic evidence. Learn more.
Deer densities have become problematic for a number of reasons, but mainly because of increased habitat and lack of predators. Sprawling development with open yards adjacent to wooded areas are deer Xanadu. Predators like pumas and wolves are gone. The number of bobcats and coyotes are too insignificant to keep pace with their prey. This one species is responsible for the loss of many other species of plants and animals (with humans obviously as the root cause).
Shade tolerant and slow-growing, witch-hazel (Hamamelis virginiana) brightens many an autumnal walk in the woods. In fall, the fruit capsules burst, ejecting seeds as far as 25 feet. This distance, far enough to insure some distance between parents and progeny, cannot bridge highways or housing developments. Thus this beloved shrub falls victim to habitat fragmentation.
Deer densities must be whittled down for our natural heritage to have a chance at survival. Report by Audubon Pennsylvania on conserving forest and managing white-tailed deer.
Habitat Fragmentation. As open areas are carved into smaller and smaller parcels, contiguous landscape is replaced with unconnected and isolated slivers. These fragments have less species with fewer populations in poorer health. Vulnerable, the natives are eventually overwhelmed by exotic invasives. These pest plants smother indigenous herbs and shrubs, which succumb to disease or starvation from lack of sunlight. A sea of development isolates natural areas, making native seed sources too far away to contribute replacements. This forest will never regenerate; it is “a perfect graveyard of buried hopes”, a la Anne of the Green Gable. Such biotic impoverishment is happening here at home and in developed landscapes across the country.
The supporting numbers. Recent studies support these observations. Following a typical pattern of fragmentation, the wild parklands that house our flora are being invaded by foreign plants, already 38% of the flora (820 species). While the majority of species in the city are still native, in sheer number of individuals, exotics are gaining. Exotics already outnumber surviving native species in Brooklyn and Manhattan, both of which have lost more than 75% of their native flora.
Marsh violet (Viola cucullata) is one of many species of the family Violaceae that is no longer found in the five boroughs.
Of 2179 species found in the city, 1359 are native (62%). Yet many of our native plants are no longer found, including such treasures as white milkweed (Asclepias variegata) and showy aster (Eurybia spectabilis). Extirpations (the localized extinction of species) have hit these and other herbaceous plants the hardest. Once there were 30 species of indigenous orchids in the five boroughs; today 80% of these are gone, including the handsome yellow lady’s slipper (Cypripedium parviflorum). The six species that survive do so in small, vulnerable populations. Four other families (fern, sedges, figworts and violets) have lost at least 50% of their representatives.
Staten Island, the least urbanized borough, has lost 44% of its original vegetation; about half were forest plants and all but five were understory plants (i.e., not trees). Today, almost 1/3 of the island’s vegetation is non-native. This hemorrhaging continues unabated today. Since 1990, Staten Island has lost more than 30% of its native flora (354 species), resulting in many more extirpations of herbaceous (our lovely wildflowers) than woody species.
How Plants Become Rare
In the New York City area, native plants become rare through two mechanisms: (1) development of open space, which shrinks available habitat, while (2) increasing low quality habitat favored by non-natives and invasives.
Common persimmon (Diospyros virginiana) is a New York State rare tree. This species, found in the Bronx and Staten Island, is vulnerable to reproductive isolation, becoming unable to produce fruit or seed.
Rarity: There are different types of rarity, but the one germane to our discussion is the limited number of individuals and/or populations distributed throughout a discrete area. This may happen naturally, due to a plant’s biology, but in our area it is largely caused by human activity.
Extirpation: The loss of a species from a specific geographic location; i.e., regional extinction. Through extirpation, ranges shrink and plant species lose the ability to draw on their breadth of ecotypes and special individuals, thus limiting the species’ ability to adapt to changing environmental conditions.
Extinction: The loss of the last individual of a species from the planet. Extinction is usually not the result of competition between species but of human activity. We humans are eradicating the planet’s flora and fauna at a magnitude equal to the mass extinction that wiped out the dinosaurs.
Species are lost through gradual, erosive activities: 3 populations of meadow beauty buried under a Home Depot here, 1 occurrence of blue-eyed grass succumbed to a ballfield there, another population of wild strawberry smothered by the invasive vine Japanese honeysuckle. These species are only locally, not globally rare, at least not yet. While these same plants still occur in our neighbors’ yards in New Jersey, Long Island and Westchester, their disappearance from the five boroughs is alarming. The world has begun to resemble the Big Apple as an increasingly urbanized place. Species that were driven extinct in New York City are in jeopardy throughout their ranges, since these same factors are at play everywhere. A dubious distinction – New York City – at the vanguard of art, finance, and native plant extinction.
Rare plants are afforded no legal protection. Here, the persimmon trees are threatened by development in southern Staten Island. Note the discharge pipe that ouflows into their habitat.
Categories of New York City rarity: (from “The Rare Plant Propagation Project”, Natural Resources Group, 2001)
Reproductive isolation: Several of most endangered plant species are dioecious (having male and female flowers borne on different individual plants). Colonies become reproductively isolated and so do not produce fruit or seed. Example: common persimmon (Diospyros virginiana) [see photo at right].
Single extant population vulnerable to extirpation: Many species native to southern United States reach northern range limit in New York City. The low number of populations is extremely vulnerable to extirpation from New York State. Example: lowland fragile fern (Cystopteris protrusa).
Wild populations growing on unprotected land: Some of rarest plants in New York State grow on private land currently proposed for development. Example: willow oak (Quercus phellos) & several unlisted but rare hybrid oaks.
Seed dispersal limited by habitat fragmentation: Many rare plants occur in remnant pockets of natural lands, sometimes several miles from the nearest similar habitat type. Seed dispersal is ineffective in the intervening urbanized matrix. Example: Nantucket juneberry (Amelanchier nantucketensis), which is also globally rare.
“Extinction of a single plant species may result in the disappearance of up to 30 other species of plants and wildlife.”
- U.S. Forest Service
How You Can Help Wildflowers
Lady fern (Athyrium filix-femina) is one of many fern species that is becoming increasingly rare in New York City.
In addition to using local ecotypes of native plants in gardens and landscapes, there are other ways to help preserve our natural heritage.
Be civically active. Development is the #1 cause of native plant destruction. Make note of open space slated for a strip mall or housing complex or active recreation area (because even settings like ball fields and golf courses eat up natural habitats). Attend community board meetings. Voice your dissent. Open space allows for passive recreation, like plant hunting, birding and hiking. Such activities nurture the naturalist in all of us.
Compost with care. Most homeowners believe it is environmentally responsible to pile lawn refuse (grass clippings, leaves, twigs) in adjacent open areas. Don’t. By dumping garden waste in woods or at property edge, you may be inadvertently overwhelming critical habitat for plants and animals! Here is an example of how misguided compost piles smothered wild blue lupine (Lupinus perennis), host plant of the tiny, Federally-endangered Karner blue butterfly (Lycaedes melissa samuelis).
Beech drops (Epifagus virginiana) lack chlorophyll and are parasitic on beech trees. The only way to save such species is through open space preservation.
Preserve open space. Work to save our natural areas. Become a member of a local land trust or conservancy devoted to preserving open space and natural resources (see Further Resources). If one doesn’t exist, consider starting your own.
Lay off the herbicide. Is it really that important to have a “weed free” yard? The struggle for pristine green carpet (aka lawn) is a struggle against nature itself. Herbicides kill the native plants on and around your property. Instead, keep turf to a minimum, and maximize color, richness and beauty with native plant gardens.
Ride with the masses. Whenever possible, take mass transit. Let your legislators know how you travel. New roadways promote sprawl and destroy and degrade habitat. If this money were instead used to bolster mass transit, we could conserve oil, preserve biodiversity and decrease sprawl.
As tempting as it may be, don't pick or collect plants from the wild. The beautiful spring ephemeral bloodroot (Sanguinaria canadensis) frequently falls victim to greedy gardeners.
No picking. Removing native plants from the wild depletes natural populations. Never take plants from parks or other open spaces. An exemption – if a site were slated for development, then the plants should be rescued and moved to another site, but ONLY if you were absolutely certain that the plants would otherwise be destroyed.
Legal protection for plants. New Jersey, New York, Pennsylvania and Connecticut all have something in common – none of these states have laws safeguarding native flora. Moreover, they have no legal protections for rare plants. An undeveloped lot chuck-full of uncommon and unique vegetation is not legally viewed as special. This site is just as likely to be built upon as a lot full of crummy weeds. This happens even at the Federal level, where most of the money from the Endangered Species Act goes towards animal protection. Let your legislators know that your flora should have rights. Flower power!
Join a botanical society. New York, New Jersey, Pennsylvania and Connecticut all have native plant societies. These groups lead tours through local fields and forests and always welcome new plant people. See our Further Resources page to learn more.
Take a walk. Head outdoors with a field guide and a friend to learn about the botanical jewels in your neck of the woods. Preservation comes to those places that are loved by people.