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Flowering rush

(Butomus umbellatus)

Photo of flowering rush
Photo credit: Kitty Kohout

Emergent aquatic perennial that can grow to be 1-5’ tall. It can also survive in water as deep as 10’.

Overview map of flowering rush classification in WI
Restricted (orange) counties

Other names for this plant include:

  • Common names: grassy rush, water-gladiolus

Classification in Wisconsin: Restricted

Ecological Threat
  • Marshes, backwaters and shorelines; form dense colonies and crowd out native species.

Leaves: These 3-sided leaves are stiff, narrow and triangular in a cross-section. They get to be 3’ tall and 0.5” wide. They may remain submerged if the water is too deep but are limp.

Flowers: White to light pink rose. Flowers have three petals, three sepals and red anthers. Terminal umbels bloom June-August; rise above leaves. Will not emerge or flower if in deep water.

Fruits & seeds: Clustered follicles with long beaks containing many seeds that are generally not viable.

Roots: Rhizomes that aid in vegetative growth also produce small bulbs, or bulblets, easily dispersed by water.

Similar species: Bur-reed (Sparganium spp.) is another shallow-water emergent roughly the same height as flowering rush and has identical leaves. However, bur-reeds have v-shaped leaves and the female flower parts look like small, spiked balls.


See the reported locations of the flowering rush in Wisconsin.

Do you know of other populations? Please send us a report.


Mechanical: Can be cut several times below the water line throughout the year. Small populations can be dug out to get all the root fragments.

Chemical: Some aquatic herbicides may control flowering rush infestations. Aquatic-approved herbicides require a permit.

Sources for content:
  • Czarapata, Elizabeth; Invasive Plants of the Upper Midwest: an illustrated guide to their identification and control. The University of Wisconsin Press. 2005. Pg. 142-143
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