The Abbott Marshlands habitats support over 900 species of plants found to date, of which 30 are endangered, threatened or rare for New Jersey. Because species vary in tolerances to depth and duration of water, but also to amount of light and other environmental features, habitats differ in the kinds of plants found in each. Flowers often provide conspicuous clues to the species present.
Along the banks of the tidal rivers and creeks, just above the high tide line, grows New York Ironweed, which in late summer has dazzling purple flowers that are irresistible to butterflies. Sneezeweed, whose bright-yellow composite flowers are formed of a round cluster of disk flowers surrounded by notched petal-like ray flowers, can also be found in such locations.
In the shallow water of Spring Lake and Sturgeon Pond, the yellow flowers of Spatterdock (Yellow Pond Lily) and the purple spikes and heart-shaped leaves of Pickerelweed are common. At the pond edges grow Swamp Rose Mallow, Swamp Milkweed, and Swamp Rose, all of which produce conspicuous bright pink flowers during summer. Less conspicuous are the flowers of Bur-reed and Cattail. In addition to these emergent species, ponds have submerged species, such as bladderwort, which catches small animal prey, and tiny floating duckweeds. The latter are the smallest flowering plants in the world.
The extensive tidal marsh communities are dominated by herbaceous (non-woody) species, including Cattail, Arrow Arum, Sweet Flag, and River Bulrush, all perennials, and annual species, such as Jewelweed, Water Hemp, and Bur Marigold, with Wild Rice common in poorly drained areas. Of these, Wild Rice and Bur Marigold are showy when flowering, and are best seen in late summer or autumn. The Wild Rice attracts flocks of blackbirds when its seeds ripen.
Shrub thickets are found as the transition is made from marsh to swamp. The flowers of Silky Dogwood and Swamp Azalea appear in spring, followed by Buttonbush and Elderberry in early summer. Beginning in spring and through autumn, a changing spectrum of flowers provides nectar and pollen for bees, hummingbirds, and other pollinators. Herbaceous flowers include Spring Bittercress, Canada Lily, and Turtlehead. Other woody species, such as Alder, Red Maple, and Swamp Ash may also appear in shrub thickets. In late autumn, the conspicuous red fruits of Winterberry, a shrub, are food for birds.
Still other species dominate in woodlands. In low-lying wet woods, trees such as Red Maple, Sweet Gum, Tupelo (Black Gum), and Pin Oak, are prevalent, and Spicebush and Arrowwood Viburnum dominate the shrub layer. Tulip Trees, Beech, and White, Chestnut, and Black Oaks are common in drier upland forests. These all set the stage for a spectacular display of color in autumn. In spring, ephemeral wildflowers of the understory abound and colors are subtle. These include blue and yellow Violets, delicate pink-striped Spring Beauty, nodding yellow Trout Lilies, white-flowered Mayapples, and pale cream bells of Wild Oats. Also during spring, ferns unfurl lush green fronds. In less disturbed woodlands along the bluffs, thickets of Mountain Laurel and Great Rhododendron may form the shrub layer, a feature that is unique for this part of New Jersey.
As seasons progress, wetlands and forests exhibit a broad color palette, reflecting the diverse plant species present. The Marshlands are a place where the mud flats of winter may be covered with 10-12 foot tall Wild Rice plants in August, where along trails carpets of Trout Lilies or Mayapples disappear by the end of spring, and where the water surface can be covered with the floating aquatic fern, Azolla, one year but not the next. Of the hundreds of species of plants found at the Abbott Marshlands, some are common, such as Jewelweed, but others, like Golden Club, occur in limited numbers only in one location. Each plant species has its own particular relationship to the marshlands and with other organisms.