Credit: Gabriel Campbell, Bugwood.org
General Information
Species Name: Butomus umbellatus
Also Known As: grassy rush, water gladiolus
Family: Butomaceae (Flowering Rush)
Growth Form: Forb (emergent aquatic)
Life Span: Perennial
Flowering Dates: June-August
Origin: Africa, Asia, Eurasia
Noxious: No
Category 2: Priority Aquatic Invasive Species
Why Is It Invasive?
Flowering rush spreads very easily and can cause several negative impacts. It displaces native vegetation and alters water quality, leading to reduced biodiversity and alterations to fish and wildlife habitat. It can impact water supply when it establishes in irrigation canals, reservoirs, and stormwater management ponds. Flowering rush also impacts water related recreational activities such as swimming, boating, and fishing by forming dense stands that restrict access to the water body.
What Does It Look Like?
General Characteristics
Flowering rush is an invasive aquatic plant species that resembles a large sedge and spreads primarily from rhizomes. It produces 20-50 aesthetically pleasing, pink flowers which grow in a cluster that resembles an umbrella. This plant can reach from 1-5 ft. (0.3-1.5 m) in height.
Flowers
Flowers comprise of three pink petals and three sepals arranged in clusters or umbels (umbrella shaped) on a flower stalk. Small buds that form in the clusters of flowers can disperse and grow into new plants.
Leaves
Leaves are linear, tall, up to 3.2 ft. (1 m) long, extend from the roots, and are dark green in color. Leaves have a triangular cross-section and tend to twist near the tip. The leaves may be erect or floating on the surface of the water.
Stems
Plants have a cylindrical stalk, up to 5 ft tall.
Seeds
The fruit is beaked which split at maturity to release the seeds. The seeds float which allows them to be easily dispersed by water.
Photos
Credit: Gabriel Campbell, Bugwood.org
Credit: Gabriel Campbell, Bugwood.org
Credit: Gabriel Campbell, Bugwood.org
Credit: Gabriel Campbell, Bugwood.org
Where Does It Grow?
Flowering rush is considered a wetland obligate and grows in only freshwater habitats. It roots in the mud and grows in shallow waters (to a depth of about 9 feet) in a variety of wetlands, particularly along the shoreline of lakes and slow moving rivers.
How Does It Spread?
Ships accidentally introduced it through dumping ballast as early as 1897, and the water garden trade introduced it as an ornamental plant for its large clusters of pink flowers. Several characteristics make flowering rush a successful invader. It comes in two reproductive types: 1) a flowering, fertile diploid and 2) a seldom-flowering, mostly sterile triploid. Diploids can spread by seed, bulbils produced in the inflorescences or on the rhizomes, and from rhizome buds and fragments. Triploids spread mostly from rhizome buds and fragments and are thought to be tolerant to a broader range of environmental conditions compared to diploids.
How Do I Control It?
Management of invasive aquatic plants involving either mechanical removal of plants or application of herbicides to public waters requires a permit. Contact the Contact the Nebraska Game and Parks Commission for more information.
Mechanical
Cutting or pulling the plant by hand or with equipment such as rakes or cutting blades could break it into fragments, allowing it to further spread. Contact the Nebraska Game and Parks Commission to determine appropriate removal methods.
Cultural
CLEAN your watercraft, trailer, angling gear and other equipment. Remove all aquatic vegetation and animal species from your equipment.
DRAIN your watercraft at the ramp by removing the boat plug and draining all live wells and ballast tanks.
DRY your watercraft, trailer and other equipment for at least 7 days before visiting another waterbody. If coming from a known zebra mussel infested waterbody, allow your watercraft and equipment to dry for at least 30 days before using them on an un-infested waterbody.
DON'T LET IT LOOSE. Do not release or transport exotic or non-native fish species to new ecosystems, and do not dump aquariums. It is unlawful to release any aquatic species into a waterbody other than the one from which it was harvested. Doing so can promote the spread of AIS.
Chemical
Application of chemicals to public waters requires a permit. Contact the Contact the Nebraska Game and Parks Commission for more information.
What Should I Do If I See It in Nebraska?
If you see flowering rush in Nebraska, you should report it to the Nebraska Game and Parks Commission's Aquatic Invasive Species (AIS) Program using their AIS Report Form. For guidance on what information to include in your report, check out our reporting tips.
References and More Information
Center for Invasive Species and Ecosystem Health
Minnesota Department of Natural Resources
Nebraska Game and Parks Commission
Nevada Department of Agriculture
North American Invasive Species Management Association
USGS Nonindigenous Aquatic Species
U.S. Fish and Wildlife Service