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Southern Water-plantain

Alisma subcordatum

Last reviewed: August 2026

Southern water-plantain is a wetland forb with small white flowers that bloom from June through August, growing in marshes, ditches and pond edges across much of the eastern and central United States.

Southern Water-plantain (Alisma subcordatum)
Photo: Robert H. Mohlenbrock. USDA NRCS. 1995. Northeast wetland flora: Field office guide to plant species. Northeast National Technical Center, Chester, PA. Courtesy of USDA NRCS Wetland Science Institute. / Wikimedia Commons (Public domain)

Toxicity unknown

Southern Water-plantain (Alisma subcordatum) is not listed by the ASPCA Animal Poison Control Center (opens in new tab) or the other sources we check, so we have no verdict for it either way. Absence from those lists is not a clearance. If your pet shows symptoms after eating any plant, call the ASPCA at (888) 426-4435.

The USDA PLANTS Database (opens in new tab) does not flag Southern Water-plantain as toxic to livestock.

Light

part sun

Water

high

Size

12"–36" H × 6"–18" W

Bloom

Jun, Jul, Aug

Native to

AL, AR, CO, CT and 34 more states

Pollinators

bees, flies

Before you buy

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Cities and water utilities offer rebates for replacing lawn with native and water-wise plants. We track 452 programs across 44 states, each with a link to the provider and the date we last checked it.

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Browse plants for this ecoregion

Southern RockiesArizona/New Mexico MountainsSouthwestern TablelandsCentral Great PlainsGreat PlainsEastern Temperate ForestsOzark HighlandsCentral Irregular PlainsPiedmontNorthern Glaciated PlainsWestern Corn Belt PlainsNorthern Lakes and ForestsNorth Central Hardwood ForestsDriftless AreaSoutheastern Wisconsin Till PlainsCentral Corn Belt PlainsEastern Corn Belt PlainsSouthern Michigan/Northern Indiana Drift PlainsHuron/Erie Lake PlainsNortheastern HighlandsNortheastern Coastal ZoneNorthern Allegheny PlateauErie Drift PlainNorthern ForestsMiddle Atlantic Coastal PlainNorthern PiedmontSoutheastern PlainsBlue RidgeRidge and ValleyCentral AppalachiansWestern Allegheny PlateauInterior PlateauInterior River Valleys and HillsMississippi Alluvial PlainAcadian Plains and HillsEastern Great Lakes LowlandsAtlantic Coastal Pine Barrens

Southern water-plantain is an aquatic perennial that thrives in wet soils and shallow water areas. It produces small white flowers in summer on tall, branching stems above broad, heart-shaped leaves. This plant requires consistently moist to wet conditions and is best suited for pond edges, rain gardens, or boggy areas.

Growing Southern Water-plantain

Grow Southern Water-plantain in part sun and high water. Mature plants reach 12 to 36 inches tall and spread 6 to 18 inches wide. Expect moderate maintenance to keep it looking intentional in a front yard.

In an HOA neighborhood

Southern Water-plantain takes more care to keep looking intentional in a front yard. Maintenance level: moderate. Consider it for backyard or mid-zone beds rather than the street edge.

Works well in: backyard only.

  • Requires specialized wet conditions that look unfinished in typical landscaping
  • Aquatic appearance may seem out of place in standard residential settings
  • Limited to very specific water garden or pond applications

Wildlife value

The summer flowers attract bees and flies for pollination. Seeds provide food for waterfowl and other birds that frequent wetland areas.

Common questions

When does Alisma subcordatum bloom?
Southern water-plantain flowers from June through August, producing small white blooms on branched stalks that rise above its rosette of leaves.
What pollinators visit Alisma subcordatum?
Bees and flies are the main visitors to its small white flowers, which offer accessible nectar and pollen typical of open-faced wetland blooms.
What growing conditions does Southern water-plantain need?
It grows best in consistently wet to saturated soil, including standing shallow water, and tolerates full sun to part shade, making it suited to pond margins, ditches and marshy meadows.
Is Alisma subcordatum a good plant for a rain garden or pond edge?
Yes, its tolerance for standing water and wet soil makes it a practical choice for the saturated zones of rain gardens, pond edges and marsh restorations.
Is Southern Water-plantain toxic to livestock?
The USDA PLANTS Database does not flag Southern Water-plantain as toxic to livestock.
Is Southern Water-plantain HOA-friendly?
Southern Water-plantain takes more care to look intentional in a front yard. Consider it for backyard or mid-zone beds rather than the street edge.

These answers were drafted with an AI model from this plant's data. Verify care details with a local expert.

Native range data from vouchered herbarium specimen records and regional native plant society lists. Pollinator and host plant associations compiled from GBIF, iNaturalist, and published ecological literature.

If something looks wrong

Common plant problems, and what to check first

These come up on almost any plant. Each guide lists the likely causes in the order they are worth ruling out, with one thing to check before you act on any of them, and links to the source it came from.

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