Schoenoplectus americanus
Three-square bulrush
Image of Schoenoplectus americanus

Photo by Dennis A. Albert 

Key Characteristics

Very tall bulrush (2 m) of salt marshes; stems strongly 3-angled with prominent wings and easily compressed; spikelets appear lateral and are densely clustered, similar to three-square (Schoenoplectus pungens).

Status and Rank

  • State Status: E
  • State Rank: S1
  • Global Rank: G5


County NameNumber of OccurrencesYear Last Observed
Distribution map for Schoenoplectus americanus

Updated 5/15/2018. Information is summarized from MNFI's database of rare species and community occurrences. Data may not reflect true distribution since much of the state has not been thoroughly surveyed.


Olney's bulrush occurs in seasonally inundated graminoid-dominated salt marshes.

Natural Community Types


For each species, lists of natural communities were derived from review of the nearly 6,500 element occurrences in the MNFI database, in addition to herbarium label data for some taxa. In most cases, at least one specimen record exists for each listed natural community. For certain taxa, especially poorly collected or extirpated species of prairie and savanna habitats, natural community lists were derived from inferences from collection sites and habitat preferences in immediately adjacent states (particularly Indiana and Illinois). Natural communities are not listed for those species documented only from altered or ruderal habitats in Michigan, especially for taxa that occur in a variety of habitats outside of the state.

Natural communities are not listed in order of frequency of occurrence, but are rather derived from the full set of natural communities, organized by Ecological Group. In many cases, the general habitat descriptions should provide greater clarity and direction to the surveyor. In future versions of the Rare Species Explorer, we hope to incorporate natural community fidelity ranks for each taxon.

Associated Plants

Common three-square, spikerush, joe-pye weed, and swamp milkweed.


The primary conservation need for this species is the maintenance of hydrology and natural disturbance regime. It may also require prescribed fire over the long-term for perpetuation.

General Survey Guidelines

Random meander search covers areas that appear likely to have rare taxa, based on habitat and the judgement of the investigator.

Survey Methods

Page Citation

Michigan Natural Features Inventory. 2007. Rare Species Explorer (Web Application). Available online at [Accessed Sep 24, 2018]


Survey References

Technical References

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