Saltmarsh morning glory has a thin vine with alternate narrow sagittate or arrowhead-shaped leaves. The vine grows along the ground until it contacts a vertical support. The vine wraps itself counter-clockwise as it grows up the support. In the above photograph, the morning glory is twined around leaves of sand cordgrass (Spartina bakeri). From personal experience, saltmarsh morning glory never seems to bloom until it is climbing a support.

Saltmarsh morning glory is a hemicryptophyte, "half hidden plant", a perennial whose above ground parts die back when seasonal conditions (a dry or cold season) are not conducive to growth. Unlike the common annual varieties of morning glories (Ipomoea nil, I. purpurea, and I. tricolor) found in gardens, the saltmarsh morning glory is a wild thing. The plant does not adapt to man-made habitats and seldom persists in gardens.