: Grassy rush, water gladiolus
: This species is listed as a restricted noxious weed by the Michigan Department of Agriculture. Flowering rush occurred in the Detroit River as early as 1918 but has become a much greater problem in recent years.
: Perennial, erect, floating or submersed in water up to 2 m (6 ft) deep.
: Linear, up to 1 m (39 in) long and 0.5-1 cm (0.2-0.4 in) wide, growing from the base, triangular in cross-section.
: Smooth; erect; round; 1-1.5 m (3-4.5 ft) tall.
: Pale pink, rose or white in color; 3 petals and 3 petal-like sepals, held in a many-flowered, rounded cluster with 3 bracts; held at the top of the stem, not all populations produce flowers although many in Michigan do.
Fruit and seeds
: Fruit a beaked follicle, not all populations produce fertile seed but at least some Michigan populations do so.
: Native to Eurasia. Found in rivers, lakes, emergent wetlands and ditches in waters up to 3 m (~10 ft) in depth.
: By stout creeping rhizomes, vegetative bulbils that form in rhizome axils, some populations produce fertile seed also, seeds float and are water-dispersed, seeds, like those of many wetland species are long-lived.
: Non-flowering specimens may resemble young bur-reeds (Sparganium spp.
) or bulrushes (Scirppus spp.
) as they may have similar leaves.
Monitoring and rapid response
: Monitor lake shores, stream banks and ditches, particular where water levels have dropped; plant is identifiable in summer when fruit or seed are present. Cutting flowering rush under water may reduce population density, remove all plant parts; digging out isolated plants may prevent spread but bulbils on rhizomes must be removed also, do not compost near wetlands or water; control with herbicide difficult. Permits are usually required for herbicide use in water bodies and wetlands. For information see MDEQs Aquatic Nuisance Control website at: https://www.michigan.gov/egle/0,9429,7-135-3313_3681_3710---,00.html
: The Michigan Natural Features Inventory
(MNFI) has partnered with MISIN to provide the information in this fact sheet. Species images and/or information were used with permission from "A Field Identification Guide to Invasive Plants in Michigan's Natural Communities
" and "A Field Guide to Invasive Plants of Aquatic and Wetland Habitats for Michigan