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A Forager’s Year

No. 94

Broadleaf arrowhead

Sagittaria latifolia

duck potato, wapato

Young shoots flower stalks, before the flowers open (cooked)

Drawing: Britton & Brown, Illustrated Flora (1913)

No modern safety review found. No extension, government, poison-center or peer-reviewed source discusses eating the flower stalks of broadleaf arrowhead; NC State lists no poisonous part of the plant and says the buds are edible, and Eat The Weeds, a foraging site, is the only source for the stalks.

Find
Common in the right habitat
Effort
Quick kitchen prep
ID risk
Careful
Origin
native
Safety marks
  • Deadly lookalike
  • Cook first
  • Spray risk
Uses
  • Cooked vegetable / soup

Season

  1. Jan
  2. Feb
  3. Mar
  4. Apr
  5. May
  6. Jun
  7. Jul
  8. Aug
  9. Sep
  10. Oct
  11. Nov
  12. Dec

in season peak

Picking: No park we checked allows it. Anywhere else, ask whoever owns or runs the land. See Where you may pick.

What these mean

Find

1 Everywhere · 2 Common in the right habitat · 3 Patchy · 4 Elusive. This is about how much there is, not whether you may pick it. It is based on iNaturalist sightings within 25 km (about 15 miles) of downtown DC, counted on October 3, 2026. The four rules that each plant’s “Find” reason refers to: (A) the estimate is the confirmed sightings, plus the unconfirmed ones (scaled down where the plant has lookalikes in its genus), plus the sightings marked as planted; (B) the tier by estimate: 1,500 or more is tier 1, 250–1,499 tier 2, 50–249 tier 3, under 50 tier 4; (C) tier 1, Everywhere, also needs a source saying the plant is common in lawns, sidewalks, yards or gardens, vacant lots or towns, or at least one DC street tree of it per km of sidewalk, otherwise it is tier 2; (D) if a reliable source says the plant is rare in this region, or that wild plants rarely bear the harvest, only planted sightings count. iNaturalist is a website and phone app where people post photos of the plants and animals they see. A sighting is “research grade” when other users have confirmed what it is; “needs ID” sightings are not confirmed yet, and “cultivated” ones are marked as planted.

Effort

1 Grab & eat · 2 Quick kitchen prep (under about 30 minutes) · 3 Real work (hours, or cooking needed for safety) · 4 Project (days or equipment). Scored on the simplest worthwhile use; each plant’s page says why.

ID risk

How hard it is to harvest safely. Beginner: no dangerous lookalike, and the edible part is not easily confused with a toxic part. Careful: a toxic lookalike, or toxic parts that end up in the harvest unless removed (for example elderberry stems, unripe ground cherries), or other parts of the plant rated medium-or-higher toxicity, with reliable features to separate them. Expert only: a potentially deadly lookalike that is hard to separate, or (for not-recommended harvests like pokeweed) a plant whose safe preparation can’t be guaranteed. Toxic parts that are obviously separate and thrown away anyway (pits, seeds, skins) don’t raise it; the Toxic parts mark carries that warning.

Native or not, and the invader stars

Origin is where the plant comes from: native, non-native, or mixed (the harvest covers both). The stars rate plants on invasive plant lists: ★★★ Virginia DCR “High” or Maryland prohibited invasive · ★★ Virginia “Medium” · ★ Virginia “Low” · ☆ listed only by the Maryland Invasive Species Council or the Mid-Atlantic Plant Invaders guide (advisory) · no stars: native or not listed.

Safety marks and flags

Deadly lookalike / Toxic lookalike: a cited source names a lookalike of that danger, recorded near DC (an iNaturalist sighting within 25 km, a DC street tree, or a Smithsonian listing for DC) and looking like the part you eat. Other lookalikes are still listed, marked “not recorded near DC” or as not looking like the part you eat. Deadly means a source says eating it may be fatal or calls it deadly, or NC State rates it high severity with life-threatening symptoms (sources sometimes disagree; for example Virginia creeper). Each plant’s Lookalikes list says how to tell them apart; “harmless (may be edible)” lookalikes are listed so you know a mix-up isn’t dangerous. Cook first: cooking is needed for safety (for daylilies it is a precaution, not a sourced requirement). Eat in moderation: a source says to limit quantity or frequency (for example oxalates in sorrels and dock, ginkgotoxin, safrole). Spray risk: a source says the plant is commonly treated with herbicide in parks or lawns (invasive control, lawn weeds) or, for ginkgo, sprayed to stop fruiting. Contamination: a source says the plant concentrates pollutants. Each plant’s Safety flags list gives the details and sources.

Seasons

Start, peak and end are given in thirds of a month: early, mid or late. A plant counts as in season for a month if it is in season at any point in that month. Some greens and roots have a second window, in spring or fall; their page shows each window. A season that runs across New Year is shown as one window.

What it looks like

The young flowering stalks of broadleaf arrowhead, a native water plant with arrow-shaped leaves (NC State), picked before the flowers open. Between July and September each plant sends up one or two tapering, cylindrical flowering stalks, taller than the leaves, that carry 2 to 15 whorls of white, three-petaled flowers (USDA). Eat The Weeds calls the stalks before the blossom a tender tidbit, to be boiled, and NC State says the buds are edible.

Safety

No part of broadleaf arrowhead is listed as poisonous (NC State). Deadly lookalike: arrow arum (tuckahoe), which grows in the same marshes with similar arrow-shaped leaves; its flowers, leaves and stems hold calcium oxalate, which affects the mouth and digestive tract unless thoroughly cooked or dried (NC State; Mississippi State University Extension). Maryland’s state archaeology museum (Jefferson Patterson Park & Museum) says swallowing arrow arum can be fatal. Arrowhead leaf veins all spread from the base of the leaf, one to each lobe (NC State; USDA), while arrow arum leaves have prominent veins down the middle and along the edge (Chesapeake Bay Program). Arrow arum blooms earlier, from spring into early summer, with a flower spike hidden in a green sheath (NC State; Chesapeake Bay Program), while arrowhead sends up slender stalks taller than the leaves between July and September (USDA). Fernald & Kinsey (1958) also name wild calla, a toxic plant with heart-shaped leaves, a white spathe and red berries (NC State), but it is not recorded near DC. Pickerelweed, which NC State says is often confused with arrowhead, has heart-shaped leaves and spikes of blue flowers (Chesapeake Bay Program; NC State) and is not toxic; its young stalks are edible (Virginia Cooperative Extension). Cook the stalks: CDC says people most often catch the liver fluke Fasciola by eating raw watercress or other freshwater plants contaminated with its larvae; Eat The Weeds boils them. Wash aquatic plants well before cooking (Virginia Cooperative Extension). Broadleaf arrowhead takes up metals from the mud and water it grows in (USDA; Restoration Ecology, 1993), so gather only from clean, unpolluted water (Eat The Weeds; Virginia Cooperative Extension). Virginia’s Department of Wildlife Resources and Mississippi State University Extension list herbicides for treating arrowhead in ponds, so ask the owner about spraying before picking. Virginia Cooperative Extension advises never harvesting aquatic plants alone and wearing boots or waders and a life vest.

Lookalikes

Safety flags

Safety marks and flags: what this means

Deadly lookalike / Toxic lookalike: a cited source names a lookalike of that danger, recorded near DC (an iNaturalist sighting within 25 km, a DC street tree, or a Smithsonian listing for DC) and looking like the part you eat. Other lookalikes are still listed, marked “not recorded near DC” or as not looking like the part you eat. Deadly means a source says eating it may be fatal or calls it deadly, or NC State rates it high severity with life-threatening symptoms (sources sometimes disagree; for example Virginia creeper). Each plant’s Lookalikes list says how to tell them apart; “harmless (may be edible)” lookalikes are listed so you know a mix-up isn’t dangerous. Cook first: cooking is needed for safety (for daylilies it is a precaution, not a sourced requirement). Eat in moderation: a source says to limit quantity or frequency (for example oxalates in sorrels and dock, ginkgotoxin, safrole). Spray risk: a source says the plant is commonly treated with herbicide in parks or lawns (invasive control, lawn weeds) or, for ginkgo, sprayed to stop fruiting. Contamination: a source says the plant concentrates pollutants. Each plant’s Safety flags list gives the details and sources.

ID risk
Careful
Why
Deadly arrow arum grows in the same marshes with similar arrow-shaped leaves, and its flowers, leaves and stems hold calcium oxalate (NC State; Mississippi State University Extension); Maryland’s state archaeology museum says swallowing it can be fatal. Arrowhead leaf veins all spread from the base of the leaf, one to each lobe (NC State; USDA), while arrow arum has prominent veins down the middle and along the edge (Chesapeake Bay Program). Arrow arum blooms from spring into early summer with a flower spike in a green sheath (NC State; Chesapeake Bay Program), while arrowhead stalks rise above the leaves between July and September (USDA). Wild calla, which Fernald & Kinsey (1958) pair with arrowhead, is not recorded near DC.
Soil risk
higher
ID risk: what this means

How hard it is to harvest safely. Beginner: no dangerous lookalike, and the edible part is not easily confused with a toxic part. Careful: a toxic lookalike, or toxic parts that end up in the harvest unless removed (for example elderberry stems, unripe ground cherries), or other parts of the plant rated medium-or-higher toxicity, with reliable features to separate them. Expert only: a potentially deadly lookalike that is hard to separate, or (for not-recommended harvests like pokeweed) a plant whose safe preparation can’t be guaranteed. Toxic parts that are obviously separate and thrown away anyway (pits, seeds, skins) don’t raise it; the Toxic parts mark carries that warning.

Soil risk: what this means

Based on the part you eat, following the urban-soil lead guidance on the Field safety page: higher for greens, shoots and roots; moderate for flowers; low for fruit, nuts and sap.

Field safety for every outing (poison ivy, ticks, soil, and more)

When to pick

Starts
early Jul
Peak
–
Ends
mid Sep

Between July and September each plant sends up one or two flowering stalks (USDA); pick them before the flowers open. Around DC, iNaturalist sightings rise from late July and are highest from late August to mid September, when most plants are in flower. No source dates the unopened stalks for the DC area, so the season is an estimate. Arrow arum, a toxic lookalike, blooms earlier, from spring into early summer (NC State; Chesapeake Bay Program).

How the dates were worked out

Every start, peak and end was re-checked in October 2026. “Sourced” means a source opened during the check states that timing for the DC or Mid-Atlantic area. “Estimated” means no source states it exactly; the reason, the evidence and the source links are under “How the dates were worked out” on each plant’s page. Peaks are often estimated, because few sources name a peak. iNaturalist evidence means research-grade sightings near DC, by month, of the plant at that stage (for example, in fruit). iNaturalist is a website and phone app where people post photos of the plants and animals they see. A sighting is “research grade” when other users have confirmed what it is; “needs ID” sightings are not confirmed yet, and “cultivated” ones are marked as planted.

Season basis: estimated: start, end

Start

estimated: No source dates the stalks for the DC area; early July is when USDA says the stalks begin to emerge and NC State (North Carolina) says flowering begins.

Peak

End

estimated: No source gives an end date for unopened stalks; mid September is the end of the July-to-September emergence USDA gives, and the last of the budding plants logged around DC.

Evidence

start: USDA fact sheet: 'Between July and September one or two tapering cylindrical flowering stalks (scapes) emerge'. NC State: 'blooming from July to September'. | end: USDA fact sheet: stalks emerge 'Between July and September'. iNaturalist: 7 DC-area sightings annotated as budding, 2 in August, 4 in September (latest in mid September) and 1 in October.

Where to look

Shallow water of marshes, ponds and slow streams; Huntley Meadows and Kenilworth Aquatic Gardens have by far the most logged plants, followed by Four Mile Run, Theodore Roosevelt Island and the C&O Canal, but all of these ban picking, so pick or dig only on private land with the owner’s permission, in clean water.

Habitats
disturbed ground & waste places, floodplain & stream-valley forest, wetlands, marshes & pond edges
Habitats: what this means

Listed where the plant’s own sources place it in that habitat. “Disturbed ground & waste places” means a cited source places it on disturbed areas, sites, soil or ground, on waste places or waste ground, on construction or abandoned building sites (old home sites count), on rubble or in strip mines. When the source gives examples of the disturbed places, at least one example must be of that kind. Examples that do not count: natural or forestry disturbance (treefall gaps, fire, windthrow, flood scour, old riverbanks and creeks, clear-cuts); roadsides, railroads and rights-of-way; and abandoned fields, pastures and farmland, which are “Old fields & meadows”. “Vacant lots” only where a source says vacant or empty lots.

Most-logged places

None of the most-logged places allows picking.

No picking here (5 places)
  • Huntley Meadows Park

    117 sightings · Legal to pick: no · see them on iNaturalist

    Look but don’t pick: Fairfax County parks ban removing any plant part without written permission.

  • Kenilworth Park & Aquatic Gardens

    105 sightings · Legal to pick: no · see them on iNaturalist

    Look but don’t pick: Kenilworth is a NACE site that is not on the compendium’s list of gathering areas.

  • Four Mile Run stream valley (Arlington/Alexandria)

    19 sightings · Legal to pick: no · see them on iNaturalist

    Look but don’t pick: Arlington County park rules (flora shall not be removed or disturbed) and Alexandria’s permit rule both apply.

  • Theodore Roosevelt Island

    15 sightings · Legal to pick: no · see them on iNaturalist

    Look but don’t pick: GW Memorial Parkway sites (incl. Great Falls VA, Theodore Roosevelt Island, Dyke Marsh) designate nothing for gathering.

  • C&O Canal NHP (towpath, Georgetown to Great Falls MD and beyond)

    13 sightings · Legal to pick: no · see them on iNaturalist

    Look but don’t pick: the C&O Canal compendium covers only edible fruits, nuts, berries and mushrooms, and NPS parks can never designate leaves, flowers, roots or sap. Of these, 3 are at Carderock.

Most-logged places: what this means

The places with the most research-grade iNaturalist sightings within 25 km of downtown DC (re-counted in October 2026 over every named place, campuses, condominiums and private grounds included), each marked legal to pick or not. A sighting inside several named places counts once, for the smallest of them, but a sighting inside a National Park Service park never counts for a private, campus or unchecked place. iNaturalist shows where people walk and log plants, not true abundance. Private campuses, condominiums, museums, estates and utility land (Pepco’s power-line land near Sligo Creek) are marked “no” (pick only with the owner’s permission); public university campuses, city parks and other places whose picking rules were not checked (county stormwater land, the U.S. Capitol Grounds, Greenbelt’s North Woods, federal facilities such as the National Zoo) are “unknown”. A place needs at least 2 sightings, so plants with very few sightings have no places. At-risk plants (butternut, nannyberry, American chestnut, ramps, riverbank goldenrod) get places like every other plant; each page says why the plant is at risk and gives any advice its sources give. For some places, mostly Rock Creek Park, the iNaturalist map shows more sightings than the count here, because a map link cannot leave out exactly the sightings credited to another place. iNaturalist is a website and phone app where people post photos of the plants and animals they see. A sighting is “research grade” when other users have confirmed what it is; “needs ID” sightings are not confirmed yet, and “cultivated” ones are marked as planted.

Ways to use it

  • boiled, picked before the flowers open (Eat The Weeds)
  • the flower buds are also edible (NC State)

Keeping

Keep cold and moist and use within a few days, or blanch and freeze.

Use within
within a few days
Keeps fresh
Keep the stalks cold and moist, like asparagus (University of Minnesota: asparagus about 2 weeks cold, moist and upright), and use them within a few days for best texture (general guidance for asparagus-type shoots).
Keeping basis
general guidance for its type

Ways to keep it

  • Freeze as researched: blanch & freeze; canning: n/a (not shelf-canned)

    No tested blanch time for arrowhead stalks. NCHFP’s asparagus times (2–4 minutes depending on thickness) are the closest general guidance; cool, drain and freeze.

Canning: what this means

Shelf-stable canning, three levels. Lab-tested: a lab-tested recipe from the National Center for Home Food Preservation (NCHFP) or Oregon State covers this fruit and product, or a generic recipe for its kind (the line says so, for example chokeberry). Extension recipe: a published Extension recipe (University of Alaska Fairbanks, written for Alaska species; University of Maine’s dandelion jelly), or a process that is safe only with a pH meter; follow it exactly, never improvise. No tested recipe: refrigerate or freeze, don’t can. “Hot-bottled syrup” = maple and walnut syrup, which keep when bottled hot at full syrup density. The Canning line names the exact product each source covers, for example “whole berries” or “juice”; a product not named there (such as juice from a berry with only a whole-berry recipe) has no tested recipe.

Keeping basis: what this means

“Specific to this plant” or “general guidance for its type” (for example NCHFP guidance for leafy greens applied to a wild green).

Nutrition

Not researched: in October 2026, only the calendar’s plants of the month and chicory leaves were researched.

Native or not

Origin
native
Native range
Canada, the central and eastern United States, Cuba, and western South America (per NC State)
Virginia invasive rank
not listed
Maryland invasive status
not listed
Native or not, and the invader stars: what this means

Origin is where the plant comes from: native, non-native, or mixed (the harvest covers both). The stars rate plants on invasive plant lists: ★★★ Virginia DCR “High” or Maryland prohibited invasive · ★★ Virginia “Medium” · ★ Virginia “Low” · ☆ listed only by the Maryland Invasive Species Council or the Mid-Atlantic Plant Invaders guide (advisory) · no stars: native or not listed.

Virginia DCR, Virginia Invasive Plant Species List (effective September 2024), verbatim: "Under the DCR Invasive Species Assessment Protocol, approved by the Virginia Invasive Species Working Group, January 2024, species were ranked as exhibiting high, medium or low levels of invasiveness based on their threat to natural communities and native species. Invasiveness rank is higher for species that: • Alter ecosystem processes, such as succession, hydrology or fire regime. • Are capable of invading undisturbed natural communities. • Cause substantial impacts on rare or vulnerable species or natural communities or high-quality examples of more common communities. • Are found widely distributed and generally abundant where present. • Disperse readily to new areas. • Are difficult to control." The list also states: "The list is for educational purposes only and has no regulatory authority."

Maryland Department of Agriculture, Maryland Prohibited Invasive Plant Law and Regulations page, verbatim: "Plants on the Maryland Prohibited Invasive Plant List may not be added to stock after the effective date and should not be sold after their phase-out period ends."

No official DC invasive plant list was found.

How the ratings were set

Find
Common in the right habitat Estimate 732 = 476 research-grade iNaturalist sightings within 25 km + 256 needs-ID sightings counted at 97% (476 of the 493 research-grade Sagittaria sightings here are broadleaf arrowhead) + 9 'cultivated' (planted) sightings (rule A); that is tier 2 by count (rule B). Final tier 2.
Effort
Quick kitchen prep Snap off flower stalks before the flowers open and boil them.
Find: what this means

1 Everywhere · 2 Common in the right habitat · 3 Patchy · 4 Elusive. This is about how much there is, not whether you may pick it. It is based on iNaturalist sightings within 25 km (about 15 miles) of downtown DC, counted on October 3, 2026. The four rules that each plant’s “Find” reason refers to: (A) the estimate is the confirmed sightings, plus the unconfirmed ones (scaled down where the plant has lookalikes in its genus), plus the sightings marked as planted; (B) the tier by estimate: 1,500 or more is tier 1, 250–1,499 tier 2, 50–249 tier 3, under 50 tier 4; (C) tier 1, Everywhere, also needs a source saying the plant is common in lawns, sidewalks, yards or gardens, vacant lots or towns, or at least one DC street tree of it per km of sidewalk, otherwise it is tier 2; (D) if a reliable source says the plant is rare in this region, or that wild plants rarely bear the harvest, only planted sightings count. iNaturalist is a website and phone app where people post photos of the plants and animals they see. A sighting is “research grade” when other users have confirmed what it is; “needs ID” sightings are not confirmed yet, and “cultivated” ones are marked as planted.

Effort: what this means

1 Grab & eat · 2 Quick kitchen prep (under about 30 minutes) · 3 Real work (hours, or cooking needed for safety) · 4 Project (days or equipment). Scored on the simplest worthwhile use; each plant’s page says why.

Sources

30 sources, each linked to the original.

  1. Rock Creek Park Superintendent’s Compendium National Park ServiceBacks up: picking rules
  2. 36 CFR 2.1 - Preservation of natural, cultural and archeological resources Legal Information Institute, Cornell Law School (text of federal regulation)Backs up: picking rules
  3. Sagittaria latifolia (Broad-leaved Arrowhead, Duck Potato, Wapato) NC State Extension Gardener Plant ToolboxBacks up: description, habitat, uses, safety, season, native or invasive status
  4. Plant Fact Sheet: Duck Potato, Sagittaria latifolia USDA NRCS Plant Materials ProgramBacks up: description, season, safety
  5. Wapato: All It’s Quacked Up To Be (Green Deane) Eat The WeedsBacks up: description, uses, safety
  6. iNaturalist research-grade observations of Sagittaria latifolia within 25 km of downtown DC iNaturalistBacks up: findability
  7. Sagittaria latifolia Willdenow (Broad-leaved Arrowhead, Duck Potato, Wapato) (Digital Atlas of the Virginia Flora) Virginia Botanical Associates (Digital Atlas of the Virginia Flora)Backs up: habitat
  8. Annotated Checklist of the Vascular Plants of the Washington-Baltimore Area, Part II: Monocotyledons (Shetler & Orli, 2002) Smithsonian Institution, National Museum of Natural History, Department of BotanyBacks up: habitat
  9. Harvesting and storing home garden vegetables University of Minnesota ExtensionBacks up: keeping
  10. Freezing Asparagus National Center for Home Food Preservation (University of Georgia)Backs up: keeping
  11. USDA PLANTS Database: Sagittaria latifolia (SALA2), native status USDA NRCSBacks up: native or invasive status
  12. Virginia Invasive Plant Species List (effective date: September 2024) Virginia Department of Conservation and Recreation, Division of Natural HeritageBacks up: native or invasive status
  13. Maryland Prohibited Invasive Plant Law and Regulations (Maryland Prohibited Invasive Plant List, updated January 2026; additions effective July 15, 2026; 'Next Plants To Be Assessed' 2026-2027) Maryland Department of Agriculture, Plant Protection & Weed ManagementBacks up: native or invasive status
  14. Non-Native Invasive Terrestrial Plant Species in the State of Maryland (updates approved through the April 18, 2024 MISC meeting) Maryland Invasive Species CouncilBacks up: native or invasive status
  15. Plant Invaders of Mid-Atlantic Natural Areas, Field Guide (Swearingen & Fulton, 2022; successor to the NPS/USFWS 5th ed., 2017) Mid-Atlantic Invasive Plant Council / Passiflora Press (hosted by Bugwood/Mid-Atlantic Invaders Tool)Backs up: native or invasive status
  16. Invasive Plants in the District DC Department of Energy & EnvironmentBacks up: native or invasive status
  17. Arrowhead, Sagittaria spp. (Publication 3735-17; Neal, Riecke & Turnage) Mississippi State University Extension ServiceBacks up: safety
  18. Arrowhead (aquatic plant ID and treatment) Virginia Department of Wildlife ResourcesBacks up: safety
  19. Tuckahoe, Arrow Arum: Peltandra virginica, Starch Storer (Green Deane) Eat The WeedsBacks up: safety
  20. Pontederia cordata (Pickerelweed) NC State Extension Gardener Plant ToolboxBacks up: safety
  21. Biology and Management of Sagittaria latifolia Willd. (Broad-leaf Arrow-head) for Wetland Restoration and Creation (Marburger, Restoration Ecology 1(4), 1993), abstract Crossref metadata record (Wiley, Restoration Ecology)Backs up: safety
  22. Edible Aquatic Plants in Farm Ponds (CNRE-127NP; Crosby, Nerrie & Gregg, 2021, reviewed 2026) Virginia Cooperative Extension (Virginia Tech and Virginia State University)Backs up: safety
  23. Arrow Arum (Peltandra virginica) Jefferson Patterson Park & Museum (Maryland Historical Trust, the State Museum of Archaeology), via the Internet ArchiveBacks up: safety
  24. Calla palustris (Wild Calla) NC State Extension Gardener Plant ToolboxBacks up: safety
  25. About Liver Flukes US Centers for Disease Control and PreventionBacks up: safety
  26. Pontederia cordata: In a PR Pickerel (Green Deane) Eat The WeedsBacks up: safety details
  27. Peltandra virginica (Green Arrow-arum, Tuckahoe) NC State Extension Gardener Plant ToolboxBacks up: safety, season
  28. Arrow Arum (Chesapeake Bay field guide) Chesapeake Bay ProgramBacks up: safety, season
  29. iNaturalist research-grade observations of Sagittaria latifolia within 25 km of Washington, DC, by month (annotated flower budding) iNaturalistBacks up: season
  30. iNaturalist research-grade observations of Sagittaria latifolia within 25 km of Washington, DC, by month (all observations) iNaturalistBacks up: season