Freshwater Tidal Marsh Display

If you stopped by the nursery the summer of 2025, you hopefully noticed our display of plants that occur in a tidal marsh. The display was inspired by Neshaminy Creek and Biles Island, two of the last remaining tidal marshes in Pennsylvania. Freshwater tidal marshes are wetlands. They are found along rivers and other bodies of water that flood. Some areas experience twice daily flooding, with water levels rising up to six feet, while others only experience tidal flooding during the highest tides of full moon, new moon, or storms.

Edge of the Woods Display inspired by Neshaminy Creek and Biles Island

Plant Adaptations in a Tidal Marsh

The vegetation of tidal marshes has evolved to withstand this twice daily inundation, as well as exposure to sun and wind. Some plants adapt to the low-oxygen environment of water-logged soils by forming roots that extend directly into the water to access oxygen. (These are called adventitious roots.) Other plants, such as Alders (Alnus) have evolved to thrive in these locations by nitrogen fixing. Their symbiotic relationship with an anerobic bacteria called Frankia, allows Alders to create nutrient-storing nodules in their roots.

Other adaptations include:

Hollow stem or spongy tissues, allowing the plant to float, such as Eupatorium fistulosum.
Gas film on their leaves that allows carbon dioxide and oxygen to move in and out of leaf tissues, even when heavy sediment blocks sunlight.
Buoyant seeds that can float and be carried to new areas.
Seeds that can stay viable for years in the soil
Large quantities of seeds for a greater probability of germination.

Plants Typically Occurring in Tidal Marshes

Other plants typically found in a Tidal marsh are: Arrow-arum (Peltandra virginica), Wapato (Sagittaria latifolia), Water-pepper (Persicaria punctata), Marsh-purslane (Ludwigia palustris), Rice cutgrass (Leersia oryzoides), Jewelweed (Impatiens capensis), Joe pye (Eutrochium fistulosum), Climbing hempweed (Mikania scandens), Purple-stemmed aster (Symphyotrichum puniceum), Mad-dog skullcap (Scutellaria lateriflora), Larch (Larix laricina), and Swamp rose (Rosa palustris), Hibiscus moeschutus (Swamp Rose Mallow).

Where Can You Find A Tidal Marsh?

Some of the last remaining examples of this ecosystem in Pennsylvania are found along the lower section of the Neshaminy Creek and Biles Island in the Atlantic Coastal Plain Conservation Landscape of Bucks County, where the curves of the creek protect these vital wetlands. Other examples in PA include Falls Township’s Penn Patriot Park, and Bristol Marsh, and along the Delaware River. Neshaminy Creek and Biles Island are home to many species of interest: rare and endangered plants, migrating birds, and animals not found elsewhere in the county.

Biles Island

Neshaminy Creek Tidal Marsh

Rare and Endangered Plants at Neshaminy Creek

Other rare plants found at Neshaminy are: Water-hemp rag-weed (Amaranthus cannabinus), showy bur-marigold (Bidens laevis), dwarf spike-rush (Eleocharis parvula), mud-plantain (Heteranthera multiflora), water-horehound (Lycopus rubellus), long-lobed arrowhead (Sagittaria calycina), river bulrush (Schoenoplectus fluviatilis), and Smith’s bulrush (Schoenoplectus smithii).

Other plants observed at Neshaminy State Park

Also observed by citizen scientists on iNaturalist: Spatterdock (Nuphar advena), sneezeweed (Helenium autumnale), and buttonbush (Cephalanthus occidentalis).

Why Freshwater Tidal Marshes are Important

They are biodiversity hotspots! Many reptiles and amphibians found in these areas are not found elsewhere in Bucks County. The tributary streams and the Delaware River serve as connections to otherwise isolated sites for wildlife in a landscape fragmented by human development. Many migrating birds rely on these wetlands for breeding.

This area also serves as a buffer for flooding and for sediment and pollution runoff from nearby developed lands by slowing the flow of water causing sediment to settle within this wetland.

Threats to these tidal marshes include invasive plant species, human development, pollution, and rising water levels due to climate change.

Growing native plants on your property and in our communities matters now more than ever as habitats are lost to development every day. We are proud to offer many of the plant species in this article, where they would thrive in moist or water-logged areas of your property.

Tidal Marsh Birds observed at Neshaminy Creek Tidal Marsh

Tidal marshes in Pennsylvania are important breeding and foraging habitats for several bird species. Results of the 2nd Breeding Bird Atlas of 2010 confirmed breeding of 26 bird species, shown in a table by the Pennsylvania Natural Heritage Program below.

Confirmed Breeding	Probable	Possible	Observed in area
American Robin	American Goldfinch	American Crow	Bald Eagle
Baltimore Oriole	American Redstart	Bank Swallow	Black Vulture
Brown-headed Cowbird	Carolina Wren	Barn Swallow	Black-crowned Night-Heron
Canada Goose	Eastern Wood-Pewee	Belted Kingfisher	Herring Gull
Carolina Chickadee	House Finch	Black-billed Cuckoo	Laughing Gull
Cedar Waxwing	House Wren	Blue Jay	Lesser Black-backed Gull
Common Grackle	Northern Cardinal	Chimney Swift	Ring-billed Gull
Dickcissel	Northern Flicker	Common Yellowthroat	Turkey Vulture
European Starling	Northern Mockingbird	Downy Woodpecker
Field Sparrow	Red-eyed Vireo	Eastern Kingbird
Gray Catbird	Rock Pigeon	Eastern Towhee
Great Blue Heron	Warbling Vireo	Fish Crow
Green Heron		Great Black-backed Gull
House Sparrow		Great Crested Flycatcher
Indigo Bunting		Hairy Woodpecker
Killdeer		Northern Rough-winged Swallow
Mallard		Red-bellied Woodpecker
Mourning Dove		Red-tailed Hawk
Mute Swan		Ruby-throated Hummingbird
Orchard Oriole		Tree Swallow
Pied-billed Grebe		White-breasted Nuthatch
Red-winged Blackbird		Wood Thrush
Song Sparrow		Yellow-billed Cuckoo
Tufted Titmouse
Willow Flycatcher
Yellow Warbler

Other birds observed in Neshaminy State Park include Wild Turkey, Osprey, Blue-gray gnatcatcher, Yellow-rumped warbler, Red shouldered hawk, Greater scaup, and Yellow-bellied sapsucker.

Reptiles and Amphibians at Neshaminy Creek Tidal Marsh

*Endangered in PA, **Threatened in PA, *** Extirpated in PA

Salamanders: Spotted Salamander, Northern Redback Salamander, Northern two-lined Salamander, Northern dusky salamander.

Frogs and Toads: Eastern Spadefoot Toad*, American Toad, Fowler’s Toad, Spring Peeper, New Jersey Chorus Frog*, Gray Treefrog, Wood Frog, Southern Leopard Frog*, Pickerel Frog, Green Frog, and Bullfrog

Turtles: Common Snapping Turtle, Common Musk Turtle, Eastern Mud Turtle***, Spotted Turtle, Wood Turtle, Eastern Box Turtle, Map Turtle, Red-eared Slider, Redbelly Turtle**, Painted Turtle