// SPECIES PROFILE · PERENNIAL · EDIBLE AQUATIC TUBER · WATERFOWL FOOD · WETLAND RESTORATION

Broadleaf Arrowhead

Sagittaria latifolia

Broadleaf Arrowhead — also widely known as Duck Potato or Wapato — is an emergent aquatic perennial found in the shallow margins of nearly every marsh, pond, and slow stream in NE Oklahoma. Its most identifiable feature is the bold, arrowhead-shaped (sagittate) leaf with pointed basal lobes, held above the water on long, succulent petioles. In summer and early fall, erect stalks rise above the foliage bearing whorls of white, three-petaled flowers — male flowers with showy yellow stamens above, female flowers below. But the plant's true gift lies beneath the mud: it produces starchy, egg-sized tubers (wapatos) that were a staple carbohydrate for Indigenous peoples across North America and remain one of the single most important waterfowl foods on the continent. In NE Oklahoma wetlands, this species anchors the intersection of food, wildlife, and water quality like few other plants.

// QUICK FACTS

Family: Alismataceae (water-plantain family)
Life cycle: Perennial emergent aquatic; dies back to tubers in winter
Native range: Throughout N. America; all US states except NV; most of Canada; into Central America
USDA hardiness: Zones 3–10 (Tulsa = 7a/7b, fully hardy)
Mature size: 1–4 ft tall above water; tubers 1–2 in diameter
Bloom: July – September (NE OK)
Flower: White, 3-petaled, 1–1.5 in wide; in whorls of 3; male above, female below
Sun: Full sun to light shade (5+ hrs for best tuber production)
Soil: Mucky, rich sediment; tolerates heavy clay and silt
Water depth: 0–12 in standing water; tolerates seasonal fluctuation
Wildlife: Premier waterfowl food (tubers) · muskrat & beaver forage · frog & fish cover
Edible: Tubers (wapatos) staple Indigenous food; flavor like water chestnut when cooked

Broadleaf Arrowhead (Sagittaria latifolia) showing classic arrowhead-shaped leaves and white flowers in whorls — *Sagittaria latifolia* in bloom — the distinctive arrowhead-shaped leaves and whorled white, three-petaled flowers are diagnostic throughout the growing season. Photo: Rooted Revival.

Identification

[ field key — leaf · flower · tuber · vs. look-alikes ]

Habit & Growth Form

Emergent aquatic perennial growing from a short, buried corm that sends out horizontal runners (stolons) through the mud, at the tips of which the edible tubers develop. Plants are variable in size (1–4 ft tall depending on water depth and fertility) and form colonies by vegetative spread. The foliage is upright and emergent, held well above the water line on succulent petioles. In deep water (12+ inches), plants may produce submerged, ribbon-like leaves instead of the emergent arrowhead form — this is the same species responding to water depth, a common source of confusion.

Leaves

The emergent leaves are the definitive identification feature: arrowhead-shaped (sagittate) with the petiole attaching at the notch between the two pointed, backward-directed basal lobes and the terminal lobe extending forward. The blade is 2–8 in long, broadly triangular to ovate, with entire margins and prominent, parallel veins. The petiole is long, thick, and spongy with internal air chambers (aerenchyma) adapted for gas exchange in saturated, anoxic sediments. Leaves are medium green, smooth (glabrous), and slightly glossy. Submerged leaves of the same plant, when present, are linear and ribbon-like, lacking the arrowhead form entirely.

Flowers

The flowers are borne in erect, emergent racemes with whorls of three flowers spaced along the stalk. The flowers are unisexual but both sexes occur on the same plant (monoecious): male flowers occupy the upper whorls, with numerous conspicuous yellow stamens at the center; female flowers occupy the lower whorls, with a central cluster of green carpels. Both sexes have 3 white, rounded petals with a yellow-green center, and 3 green sepals. Flowers are 1–1.5 in across and open for a single day, with male flowers typically opening first (protandry). Pollination is by bees, flies, and beetles.

Tubers (Wapatos)

The most ecologically and culturally significant part of the plant is the terminal tuber formed at the tip of a long stolon in late summer and fall. The tuber is round to egg-shaped, 1–2 in in diameter, with a dark brown to bluish-purple skin and a crisp, white, starchy interior. The tuber has a distinct ring of scale-like buds at the apex. When broken free from the stolon, the tuber floats — an adaptation that allows waterfowl and currents to disperse it to new locations. The flavor when cooked is mild and nutty, similar to water chestnuts, with a texture like a firm potato.

Habitat & Range in NE Oklahoma

Sagittaria latifolia has one of the widest distributions of any North American aquatic plant, occurring in every US state except Nevada and across most Canadian provinces south of the tundra. In Oklahoma, it is common throughout the state wherever standing or slow-moving water is found. In NE Oklahoma, it is ubiquitous in the shallow margins of farm ponds, natural marshes, sloughs, roadside ditches that hold water through summer, and the quiet edges of creeks and rivers.

The species is especially abundant in the alluvial lowlands of the Arkansas, Verdigris, and Grand River systems, where it colonizes backwaters, cutoff meanders, and the shallow, still-water areas created by beaver dams. It is a dominant emergent plant of the upper reaches of Oklahoma's large reservoirs — in the shallow coves of lakes Eufaula, Hudson, Fort Gibson, and Oologah, arrowhead forms extensive stands that retreat and advance with annual water level fluctuations. Along the Illinois River, it lines the quieter pools and back eddies in association with water willow (Justicia americana).

Ecology & Wildlife Value

[ waterfowl food · mammal forage · fish habitat · wetland restoration ]

Waterfowl & the "Duck Potato"

The tubers of Sagittaria latifolia are arguably the most important natural waterfowl food in North American freshwater wetlands. Mallards, wood ducks, northern pintails, gadwall, teal (blue-winged and green-winged), and Canada geese all consume the tubers heavily during fall migration and winter. The tubers are exceptionally rich in carbohydrates and provide the high-energy fuel that migrating and overwintering waterfowl require. Ducks and geese access the tubers by dabbling and tipping up in shallow water or by probing the mud with their bills. The tubers' buoyancy when detached makes them available even after water levels rise. The plant is so closely associated with waterfowl that the most common colloquial name is simply "Duck Potato."

Mammals, Fish, & Invertebrates

Muskrats are major consumers of arrowhead tubers and stems, and their feeding and burrowing activities actually enhance tuber production by disturbing the soil and freeing tubers for colonization. Beavers eat the foliage and petioles. The dense underwater architecture of leaves and petioles provides critical nursery habitat for juvenile fish, including bass, bluegill, and crappie. Frogs, toads, turtles, and aquatic snakes use arrowhead beds for cover and basking. The flowers are visited by a variety of solitary bees, syrphid flies, and beetles.

Wetland Restoration & Water Quality

Sagittaria latifolia is a workhorse species in wetland restoration and constructed treatment wetlands. Its rapid vegetative spread stabilizes the sediment-water interface, reducing turbidity and erosion in shallow water. The extensive, fibrous root system and the spongy petioles oxygenate the rhizosphere, supporting microbial communities that break down organic pollutants and process excess nitrogen and phosphorus from agricultural and urban runoff. In biofiltration studies, mixed stands of arrowhead, rushes, and pickerelweed routinely achieve 50–80% reductions in dissolved nitrogen and phosphorus in stormwater.

Seed Dispersal & Colonization

The small, beaked seeds (achenes) are dispersed by water and by adhesion to the feathers, feet, and bills of waterfowl — a classic example of epizoochory. This relationship between arrowhead and waterfowl is mutualistic: ducks receive high-energy food from the tubers, and in return, they disperse the plant's seeds across the landscape. Arrowhead seeds are also consumed directly by some waterfowl and shorebird species. This dual dispersal strategy (viable seeds passing through digestive tracts, plus external adhesion) makes arrowhead one of the first native aquatic plants to colonize newly created or restored wetlands.

Wetland restoration plantings: For a functional constructed wetland in NE Oklahoma, plant arrowhead in the shallow margin zone (0–12 in water depth) alongside pickerelweed and common rush for maximum water purification and wildlife value. These three species form the core shallow-water community in restored and natural wetlands throughout the region.

Horticulture & Care

[ siting · planting · water depth · propagation · harvest ]

Site selection & planting

Broadleaf Arrowhead requires full sun (5+ hours) and shallow standing water or consistently saturated mucky soil to thrive. In NE Oklahoma, plant tubers or container-grown specimens in spring (April) after the soil has warmed. Ideal sites include the shallow shelf of ornamental ponds (0–8 in water depth), the edge of natural ponds, the bottom of rain gardens that pond water, and constructed wetlands. For contained settings, plant in a wide, shallow aquatic basket filled with heavy garden soil, topped with pea gravel, and set 4–12 inches below the water surface.

Water depth: 0–12 in; optimum tuber production at 2–8 in. Plants survive in deeper water but produce only submerged leaves.
Soil: Heavy, mucky garden soil or clay-loam; avoid lightweight commercial potting mixes that float.
Spacing: 12–18 in apart; colonies fill in rapidly by stolons.

Propagation & tuber harvest

Tuber planting: Simply push a tuber into the mud 1–2 inches deep in fall or early spring. Tubers float if not buried; hold in place with a small stone or gravel until rooted.
Seed: Collect mature achenes from the seed heads in late fall. Sow in wet mud in early spring; seeds require light and alternating temperatures for germination. Seedlings are slow the first year.
Division: Divide plant colonies in spring by cutting sections of the corm and stolon system with attached tubers and replanting.
Tuber harvest: Harvest from late fall through winter by wading in shallow water and feeling in the mud around the base of plants with bare feet or gloved hands. Detached tubers float to the surface, where they can be collected. This traditional harvesting technique is known as "treading" and was practiced by Indigenous peoples across the continent.

Companion planting

For wildlife ponds and constructed wetlands, combine arrowhead with: pickerelweed for blue-purple flower spikes through summer; common rush and Torrey's rush for vertical stem structure and bank stabilization; sweet flag for aromatic foliage on the shallow shelf; buttonbush for shrub structure on the bank; and American lotus in deeper water for architectural contrast. This layered community mirrors the natural plant zonation of NE Oklahoma marshes.

Edible & Cultural Uses

The tubers of Sagittaria latifolia (wapatos, "Indian potatoes," or "swan potatoes") were a major staple food for Indigenous peoples across North America, from the Algonquian nations of the Great Lakes (where the Ojibwe name wapatowa gives us "wapato") to the Siouan- speaking Osage and Quapaw of the Arkansas and Mississippi Valleys, to the Caddoan-speaking Pawnee and Arikara of the central Plains, to the Cherokee, Choctaw, Chickasaw, and Creek of the Southeast. The name "Wapato" entered English via Chinook Jargon from the Klikitat people of the Pacific Northwest, where a related species was also a staple.

Harvest & preparation: Tubers were harvested in fall and winter by wading into marshes and freeing tubers from the mud with the feet, then collecting them as they floated. Ducks were sometimes observed to locate productive beds. Tubers can be eaten raw (crisp, nutty), boiled, roasted, baked, or dried and ground into flour. The skin is thin and edible, though sometimes peeled for flour production. Boiled tubers have the texture and flavor of water chestnuts or mild potatoes.
Drying & storage: Tubers were traditionally dried and stored for winter use, either strung on cords or stored in underground caches. When dried, they can be reconstituted by boiling or ground into a nutritious, starchy flour for bread and porridge.
Nutrition: Tubers are approximately 20–25% carbohydrate (primarily starch) with modest protein (2–4%) and fiber. They provide reliable calories in a landscape where other carbohydrates may be scarce in winter.
Ecological harvest: Harvesting arrowhead tubers stimulates the plant colony by breaking stolons and distributing tuber fragments, increasing overall production the following year. Indigenous harvest practices were essentially a form of cultivation, managing and enhancing wild stands for sustained yield over centuries.

Photo Reference

// Sagittaria latifolia — flowering habit
Wikimedia Commons

// Sagittaria latifolia — foliage & form
Wikimedia Commons

// Sagittaria latifolia — flower detail
Wikimedia Commons

// Sagittaria latifolia — in habitat
Wikimedia Commons

// Sagittaria latifolia — fruit / seed
Wikimedia Commons

Sources & Further Reading

USDA NRCS PLANTS Database — Sagittaria latifolia: plants.usda.gov/plant-profile/SALA2
USDA NRCS Plant Guide — Broadleaf Arrowhead (SALA2), National Plant Data Center.
Lady Bird Johnson Wildflower Center — Native Plant Database: wildflower.org — SALA2
Kuhnlein, H.V. & N.J. Turner (1991). Traditional Plant Foods of Canadian Indigenous Peoples. Gordon and Breach — extensive wapato documentation.
Deur, D. (2002). Plant cultivation on the Northwest Coast: a reconsideration. Journal of Cultural Geography 19(2):9–35 — wapato cultivation.
Oklahoma Biological Survey — aquatic plant atlas: distribution and ecology of Sagittaria spp.
Flora of North America, Vol. 22 — Alismataceae treatment, incl. Sagittaria latifolia.
Wikipedia — Sagittaria latifolia: en.wikipedia.org/wiki/Sagittaria_latifolia (CC BY-SA 4.0; portions of description summarize Wikipedia content).
Moerman, D.E. (1998). Native American Ethnobotany. Timber Press — Sagittaria entries.

Hero photo: Rooted Revival. Strip photos courtesy of Wikimedia Commons contributors under their respective licenses (linked under each image).