Marsh elder is a perennial, deciduous shrub commonly growing between 3-8 feet high. The succulent leaves are egg-shaped to narrowly lance-shaped and oppositely arranged except for the upper reduced leaves. The lower leaves grow 4-6 inches long and 1-2 inches wide. Many greenish-white flower heads are arranged on terminal stems subtended by tiny green, leaf-like appendages. It is often confused with groundsel (Baccharis halimifolia) which exhibits succulent, coarsely-toothed leaves alternately arranged on the stem.