Leaves: Emergent leaves are stiff, narrow, green, and can grow up to 0.9 m (3 ft) above the water’s surface. Leaf tips may be spirally twisted. Submersed leaves are limp under water and do not flower.

Flowers: Grow in umbrella-shaped clusters on a long stalk with each flower made up of three petals, three sepals, and red anthers. Flowers are approximately 2.5 cm (1 in) across and are typically white, pink, or purple. Flowering occurs in late summer to early fall and only occurs on emergent plants.

Fruits/Seeds: Pistils ripen into dark brown fruits filled with tiny seeds.

Stems/Roots: Green stems are triangular in cross-section. The extensive root system is a thick creeping rhizome. Bulblets that form on the rhizome can easily break off when disturbed and form a new plant.

Similar Species

Leaves of flowering rush resemble another shallow water plant, bur-reed (Sparganium spp.); however, the leaves of the bur-reed are V-shaped and its female flowers appear as small spiked balls. Bur-reed grows 0.3-1.2 m (1-4 ft) tall.

Habitat

Flowering rush prefers shallow and slow-moving waters but will inhabit deeper waters. It grows well in riparian zones, watercourses, and wetlands such as ditches, marshes, lakes, or streams. It cannot grow in shade and requires wet soil.

Spread

Once in a watershed, flowering rush spreads locally by underground rhizomes, root pieces, and seeds. Wildlife, water movement (water or ice), anglers, and boaters can carry this plant to new areas. Its use as a water garden plant could have also contributed to its spread over long distances.

Distribution

Native to Europe and Asia, flowering rush was brought to North America as a garden plant. It is present in states along the U.S./Canadian border, extending north to the tip of Quebec and south to Illinois. In the Mid-Atlantic, flowering rush is found in New York and Pennsylvania.

Note: Distribution data for this species may have changed since the publication of the Mid-Atlantic Field Guide to Aquatic Invasive Species (2016), the source of information for this description.