Natural Communities of NH -- Photo Guide

Emergent marsh  (S5)


(formerly medium-depth emergent marsh and deep emergent marsh - aquatic bed communities)

Emergent marshes are saturated to semi-permanently flooded herbaceous wetlands with seasonably variable water levels. They occur throughout the state, and are characterized by herbaceous plants with spongy tissue (aerenchyma) emerging above the surface of the water. In most years, they remain inundated by shallow to moderately deep water throughout the growing season (generally less than 3 feet of water). During drought years, water levels may drop below the surface in relatively shallow examples.

This community occurs on silt and fine to medium-grained sand or muck along streams, rivers, lakes, and ponds. Scattered patches of fibric organic material are common. In examples with relatively shallow water, the ground surface is saturated in most years, and inundated by several inches to a foot or so of water for most of the growing season. The surface may be exposed during dry periods. Those with deeper water are semi-permanently inundated by two or three feet of water and the ground is only exposed during severe droughts. Submersed and floating-leaved species are often present among the emergents.

On low- to moderate-energy shores, plant height is relatively low and the soil is typically fine to medium-grained sand. On lower-energy shores, taller plants may occur with the low-growing species. Low-energy shorelines that are exposed for longer periods are classified as meadow marshes. Infrequently exposed zones with deeper water are classified as aquatic bed community.

Characteristic vegetation: The community is dominated by aerenchymatous (spongy tissue) herbaceous plants that emerge above the surface of the water. These include bur-reeds (Sparganium spp.), common arrowhead (Sagittaria latifolia), arrow arum (Peltandra virginica), pickerel weed (Pontederia cordata), rushes (Juncus spp.), softstem bulrush (Schoenoplectus tabernaemontani), water bulrush (Schoenoplectus subterminalis), three-way sedge (Dulichium arundinaceum), and common cattail (Typha latifolia). Less frequent species include swamp candles (Lysimachia terrestris), false pimpernel (Lindernia dubia), water purslane (Ludwigia palustris), and mannagrasses (Glyceria spp.), among others. Floating-leaved aquatics that may be present include white waterlily (Nymphaea odorata), variegated yellow pondlily (Nuphar variegata), pondweeds (Potamogeton spp.), and bladderworts (Utricularia spp.). The combination of species at a given location depends on factors such as water depth and amplitude of water level fluctuations.

A total of twenty rare plant species occur in New Hampshire’s emergent marshes, including several bur-reeds, bulrushes, and spike-rushes.


Good examples
of this community can be seen along the Blackwater River (Salisbury), Exeter River (Exeter), and Powwow River (Kingston), and around most ponds in the state.

Emergent marshes often occur as part of larger emergent marsh - shrub swamp systems and low-gradient silty-sandy riverbank systems.


 emergent marsh community at Turtletown Pond in Concord (photo by Dan Sperduto for the NH Natural Heritage Bureau)
emergent marsh community at Turtletown Pond in Concord (photo by Dan Sperduto) 

emergent marsh community in Canterbury (photo by Dan Sperduto)
emergent marsh community (foreground) in Canterbury (photo by Dan Sperduto)

emergent marsh community in a shallow pond at Pisgah State Park (photo by Ben Kimball)
emergent marsh community in a shallow pond at Pisgah State Park (photo by Ben Kimball)

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