Life in the High Marsh


Seaside Goldenrod

Special to The Star
Published: Thursday, November 7, 2013 at 11:16 AM.

By Tom Baird


The seasons are turning and while elsewhere people are enjoying the autumn foliage, we can witness impressive seasonal changes in the bay and gulf. Nowhere is this more dramatic than the plants of the upper salt marsh. The upper marsh responds to the seasons and the sea’s touch with varying colors. Seaside goldenrod displays bright bits of color and sea oxeye daisy (Borrichia frutescens) and salt marsh aster (Aster tenuifolius) create bands of color in the zones where they grow. The salt pannes or salt barrens now blaze red with glasswort and these same salt flats may have purslane in bloom. Sea lavender has sent up sprays of delicate purple flowers that make the upper marsh look like it is covered by a lavender mist. The plants of the marsh tell the seasons as clearly as the trees in a forest.

Irregularly flooded by the highest tides and visited by many terrestrial animals, the upper marsh is intimately linked to the regularly flooded lower marsh and eventually to the sea beyond. Plants of the upper marsh contend with extremes of salinity and drying. The majority are halophytes, salt tolerant plants that exhibit modifications and adaptations to their habitat. Succulents and plants with a thick waxy cuticle keep water loss to a minimum. In some marsh plants, salt glands secrete the excess salt taken in from the soli and tides. Salt crystals sparkle from their leaves on dry sunny days. Other plants resolve the salt problem by preventing salt uptake by the roots.

Definite zonation patterns based on their abilities to tolerate salt and drying characterize upper marsh plants. The plant dominating the irregularly flooded high marshes of the Atlantic and Gulf coasts is needle rush or black rush (Juncus roemerianus). Growing on higher ground and generally behind the more productive cord grass, this is the plant that often looks dead and brown. In some sections of the bay, the high marsh is characterized by salt-meadow hay (Spartina patens) and spike grass or salt grass (Distichlis spicata). More birds nest in this zone than anywhere else in the marsh.

Growing mixed with the salt grass in the same zone is the more attractive, but less abundant plant, sea lavender (Limonium carolinianum). Salt glands on this perennial herb help it withstand submersion in seawater. During most of the year the plant is low growing and inconspicuous; then, in a period of less than a week, it flourishes into a showy, delicate, multi-branched spray of tiny lavender blossoms. The high marsh glows with purple flowers, and the migrating butterflies love the nectar.

Parts of the marsh receive such little tidal flooding or run-off from the land that evaporation causes the soil salinity to become excessively high. Only a select few plants are adapted to these harsh salt barrens. One of the few plants able to grow in the salt barrens is glasswort (Salicornia), found worldwide in tropical and temperate regions. The plant is composed largely of succulent, salt-filled, oppositely branching, jointed stems. The genus name, Salicornia, is derived from the Latin sal, meaning “salt” and cornu, meaning “horn,” referring to the plant’s saltiness and horn-shaped stems. Its reduced scaly leaves make the plant appear to the leafless. Glasswort is edible – snap off some and try it – and is used for making pickles or in salads, but is also valuable simply for the variety it adds to the marsh with its fire-red autumn coloration.

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