Marshelder, Giant Sumpweed

[Cyclachaena xanthifolia (Nutt.) Fresen.]

(formerly Iva xanthifolia Nutt.)

Asteraceae (Sunflower Family)

▲ seedling

▲ ▼ young plants

▲ immature plants

▲ ▼ leaf characteristics

▲ mature plant

▲ inflorescence

Marshelder: (pp. 154-155, Weeds of the Great Plains; not in Weeds of the Northeast)

·      Also called sumpweed; summer annual weed growing 3-8’ tall in agronomic and horticultural crops; also found on roadsides, ditches; can form large, dense colonies

·        Prefers moist soil

·        Leaves opposite, triangular with palmate veining

·        Flowers small, greenish in terminal panicles

·        More common in northern Missouri and along Missouri & Mississippi rivers