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A Forager’s Year

No. 128

Pickerelweed

Pontederia cordata

pickerel weed

Nut & seed ripe seeds (raw, parched or dried)

Drawing: Britton & Brown, Illustrated Flora (1913)

Find
Common in the right habitat
Effort
Grab & eat
ID risk
Careful
Origin
native
Safety marks
  • Deadly lookalike
  • Toxic lookalike
  • Spray risk
Uses
  • Eat raw / salad
  • Baking & desserts
  • Flour
  • Roasted nuts

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: The rules are unclear. Ask the park. 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

Pickerelweed is a native water plant up to about 4 feet tall that forms large colonies along shallow shorelines, with glossy, heart- to lance-shaped leaves and dense spikes of lavender-blue flowers from summer through fall (NC State). Each small, oblong fruit holds one seed with toothed ridges (NC State) and is about 1/6 to 1/4 inch long (Native Plant Trust). After blooming, the flower spikes droop and release the seeds into the water (National Park Service). Each fruit contains a nutritious, starchy seed (Lady Bird Johnson Wildflower Center); Virginia Cooperative Extension calls the roasted seeds tasty, and Eat The Weeds says they are excellent parched for a few minutes.

Safety

No toxicity is reported for pickerelweed in the sources checked; NC State, Virginia Cooperative Extension and Mississippi State University Extension say the seeds can be eaten raw or cooked. Deadly lookalike: arrow arum often grows near pickerelweed and can be confused with it (Chesapeake Bay Program). Arrow arum has a white flower spike inside a green sheath that becomes a dark, drooping pod full of large green seeds (Chesapeake Bay Program), and it contains calcium oxalate, which affects the mouth and digestive tract if eaten (NC State); Maryland’s state archaeology museum (Jefferson Patterson Park & Museum) says swallowing it can be fatal. Gather seeds only from spikes that bore blue flowers: pickerelweed’s small, one-seeded fruits have toothed ridges (NC State). Lizard’s tail, which NC State says is often confused with pickerelweed, has white flowers on drooping spikes that become small, warty fruits, and its foliage is toxic to cattle and sheep in large amounts (NC State). Duck potato (broadleaf arrowhead), also often confused with pickerelweed, has white, 3-petaled flowers, and its fruits are edible (NC State). Pickerelweed takes up copper and lead from the mud, more in polluted areas and mostly into its roots and rhizomes (Aquatic Botany, 1982); no source has measured metals in the seeds. Harvest only from a clean water source (Virginia Cooperative Extension), and eat the seeds raw only if they come from wholesome water (Eat The Weeds). The US Geological Survey reports that water quality in the rebuilt Kenilworth Marsh and nearby tidal waters of the Anacostia has not noticeably improved. Pond owners may treat pickerelweed with herbicides such as diquat, 2,4-D, glyphosate or imazamox (Virginia Department of Wildlife Resources; Mississippi State University Extension), so ask before picking from a pond. Never harvest aquatic plants alone; wear boots or waders and a properly fitting life vest (Virginia Cooperative Extension).

Lookalikes

  • Arrow arum (tuckahoe) Peltandra virginica deadly

    Arrow arum often grows near pickerelweed and can be confused with it; arrow arum has arrowhead-shaped leaves and white flowers, pickerelweed heart-shaped leaves and blue flowers (Chesapeake Bay Program). Arrow arum’s white flower spike sits inside a green sheath and becomes a dark, drooping pod full of large green seeds (Chesapeake Bay Program), while pickerelweed’s small, oblong, one-seeded fruits with toothed ridges form on the spike that bore the blue flowers (NC State). Arrow arum contains calcium oxalate, which affects the mouth and digestive tract if eaten (NC State), and Maryland’s state archaeology museum (Jefferson Patterson Park & Museum) says swallowing it can be fatal.

  • Lizard’s tail Saururus cernuus toxic

    NC State lists lizard’s tail as often confused with pickerelweed. Lizard’s tail has upright, branching, zigzag stems, palmately veined, heart-shaped leaves that smell of citrus, and fragrant white flowers on drooping spike-like racemes that become small, green, warty fruits ripening to brown (NC State); pickerelweed’s leaves rise straight from the rhizomes and its flowers are lavender-blue (NC State). Overeaten young shoots and leaves can be toxic to sheep and cattle (NC State).

  • Broadleaf arrowhead (duck potato) Sagittaria latifolia harmless (may be edible)

    NC State lists broadleaf arrowhead as often confused with pickerelweed. It has white, 3-petaled flowers in whorls of three and round, fuzzy, green fruits that ripen to light brown, also in whorls of three (NC State), unlike pickerelweed’s dense spike of lavender-blue flowers (NC State). Its tubers, buds and fruits are edible (NC State).

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
Arrow arum, which a Maryland state museum says can be fatal if swallowed, often grows beside pickerelweed and can be confused with it (Chesapeake Bay Program; Jefferson Patterson Park & Museum), and NC State names lizard’s tail, whose foliage is toxic to livestock, as often confused with it. Take seeds only from spikes that bore lavender-blue flowers: arrow arum has a white flower spike in a green sheath that becomes a dark pod of large green seeds (Chesapeake Bay Program), and lizard’s tail has white flowers on drooping spikes and small warty fruits (NC State). Duck potato, also confused with pickerelweed, has white 3-petaled flowers and is edible (NC State).
Soil risk
low
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 Aug
Peak
early Sep–late Sep
Ends
early Nov

Pickerelweed blossoms in summer and seeds in fall (Eat The Weeds); in North Carolina, NC State says the fruit displays from June to November. Around DC it flowers mostly from June into September, with a few spikes still blooming in October (iNaturalist). No source gives seed dates for the DC area, so these dates are estimates. Ripe seeds fall into your hand at a touch (Virginia Cooperative Extension), and the spent spikes droop and drop their seeds into the water (National Park Service), so check stands every week or so.

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, peak, end

Start

estimated: No source dates ripe seed for the DC area; flowering starts in June here, and early August allows for the first spikes to set ripe seed, between NC State’s June start in North Carolina and the fall that Eat The Weeds gives.

Peak

estimated: No source names a peak; September is the start of the fall seeding that Eat The Weeds gives, after the June and July flowering logged around DC.

End

estimated: No source gives an end date for the DC area; early November covers seed from the last October flowers and NC State’s November end in North Carolina, after which sightings stop.

Evidence

start: NC State (North Carolina): fruit 'Displays from June to November.' Eat The Weeds: 'Blossoms in summer seeds in fall'. National Park Service (Kenilworth): 'In early summer, the lotus flowers emerge and the pickerel weed flowers.' iNaturalist (25 km of DC, flowering annotations): May 2, June 37, July 32. | peak: Eat The Weeds: 'Blossoms in summer seeds in fall'. iNaturalist (25 km of DC, flowering annotations): June 37, July 32, August 8, September 32, October 9. | end: NC State (North Carolina): fruit 'Displays from June to November.' iNaturalist (25 km of DC): flowering annotations October 9, November 1; all research-grade sightings October 127, November 28, December 0.

Where to look

Shallow edges of the tidal Potomac and Anacostia, ponds and marshes; logged most at Kenilworth Aquatic Gardens, along the C&O Canal, at Lake Artemesia and at Dyke Marsh. Kenilworth, Lake Artemesia, Dyke Marsh and Glencarlyn Park ban picking; the C&O Canal and Virginia state parks such as Mason Neck allow edible fruits and nuts generally but do not say whether pickerelweed seeds count, so they are ambiguous there (ask the park). Otherwise gather only on private land with the owner’s permission, from a clean water source.

Habitats
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.

Ask first: rules unclear or not checked

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

    186 sightings · Legal to pick: ambiguous · see them on iNaturalist

    Ambiguous: the C&O compendium allows edible fruits, nuts and berries generally but sets no limit for this one; ask the park first. Of these, 1 is at Carderock.

No picking here (4 places)
  • Kenilworth Park & Aquatic Gardens

    330 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.

  • Lake Artemesia Natural Area

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

    Look but don’t pick: Montgomery/Prince George’s parks (M-NCPPC) ban harvesting vegetation without a permit.

  • Dyke Marsh Wildlife Preserve

    63 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.

  • Glencarlyn Park

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

    Look but don’t pick: Arlington County park rules say flora shall not be removed or disturbed.

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

  • eaten raw, straight from the plant (Lady Bird Johnson Wildflower Center; NC State)
  • parched or roasted for a few minutes and eaten like a nut or as a trail snack (Eat The Weeds; Virginia Cooperative Extension)
  • boiled like rice (Eat The Weeds; Virginia Cooperative Extension)
  • dried and ground into flour, or tossed into a bread recipe (Virginia Cooperative Extension; Eat The Weeds)
  • dried and added to granola or other cereals (Lady Bird Johnson Wildflower Center; Mississippi State University Extension)
  • harvest the seeds when they fall into your hand right off the plant (Virginia Cooperative Extension; Eat The Weeds)

Keeping

Eat them fresh or dry them soon after gathering, and keep the dried seeds or flour airtight in a cool, dark place for up to about a year.

Use within
within a few days
Keeps fresh
The seeds can be eaten fresh, straight from the plant (Lady Bird Johnson Wildflower Center); no source gives a keeping time for fresh seeds. Start drying them soon after harvest, usually within 24 hours (general guidance for nuts and seeds, WSU).
Keeping basis
general guidance for its type

Ways to keep it

  • Dry as researched: dry/dehydrate; canning: n/a (not shelf-canned)

    Dried seeds make a good grain for bread and flour (Eat The Weeds) and can be added to granola or cereal (Lady Bird Johnson Wildflower Center; Mississippi State University Extension). Store dried food airtight in a cool, dry, dark place; recommended storage times for dried foods are 4 months to 1 year (general guidance for dried foods, NCHFP).

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
E. North America to Caribbean (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 1,613 = 1,465 research-grade iNaturalist sightings within 25 km + 52 needs-ID sightings counted at 97% (1,465 of the 1,512 research-grade Pontederia sightings here are pickerelweed) + 98 'cultivated' (planted) sightings (rule A); that is tier 1 by count (rule B). Rule C: none of its sources says it is common in, or a weed of, an everyday place (lawns, sidewalks, yards or gardens, vacant lots, towns), so it cannot be tier 1 (Everywhere). Rule D does not apply: the Digital Atlas of the Virginia Flora says pickerelweed is "rare in the inner Piedmont and mountains", but the same atlas calls it "Common in the Coastal Plain", which takes in part of the 25 km circle, and a source that calls the plant common in one part of the circle outweighs its rare statement about another part. Final tier 2.
Effort
Grab & eat Gather the ripe seeds that fall into your hand from the spike and eat them raw; parching or roasting them is a 2, and drying and grinding them into flour is a 3.
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

35 sources, each linked to the original.

  1. C&O Canal NHP Superintendent’s Compendium, effective September 11, 2026 National Park Service, Chesapeake and Ohio Canal NHPBacks up: picking rules
  2. Rock Creek Park Superintendent’s Compendium National Park ServiceBacks up: picking rules
  3. 4VAC5-30-50. Flowers, plants, minerals, etc. Virginia Law Library (law.lis.virginia.gov)Backs up: picking rules
  4. 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
  5. Pontederia cordata (pickerelweed), Go Botany Native Plant TrustBacks up: description
  6. Freshwater Marsh Plants National Park Service, Kenilworth Park & Aquatic GardensBacks up: description, season, habitat
  7. Pontederia cordata (Pickerelweed) Lady Bird Johnson Wildflower CenterBacks up: description, uses, keeping
  8. iNaturalist research-grade observations of Pontederia cordata within 25 km of downtown DC iNaturalistBacks up: findability
  9. Plant Fact Sheet: Pickerelweed, Pontederia cordata L. USDA NRCS Plant Materials ProgramBacks up: habitat
  10. Annotated Checklist of the Vascular Plants of the Washington-Baltimore Area, Part II: Monocotyledons (Shetler & Orli, 2002) Smithsonian Institution, National Museum of Natural HistoryBacks up: habitat
  11. Wetland Restoration Anacostia Watershed SocietyBacks up: habitat
  12. Pontederia cordata L. var. cordata (Pickerelweed) (Digital Atlas of the Virginia Flora) Virginia Botanical Associates (Digital Atlas of the Virginia Flora)Backs up: habitat, findability
  13. Food Safety and Preservation: Nuts & Seeds Washington State University Extension, Lewis CountyBacks up: keeping
  14. Packaging and Storing Dried Foods National Center for Home Food Preservation (University of Georgia)Backs up: keeping
  15. USDA PLANTS Database: Pontederia cordata (POCO14), native status USDA NRCSBacks up: native or invasive status
  16. Virginia Invasive Plant Species List (effective date: September 2024) Virginia Department of Conservation and Recreation, Division of Natural HeritageBacks up: native or invasive status
  17. 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
  18. 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
  19. 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
  20. Invasive Plants in the District DC Department of Energy & EnvironmentBacks up: native or invasive status
  21. Arrow Arum (Peltandra virginica), Chesapeake Bay field guide Chesapeake Bay ProgramBacks up: safety, effort & ID risk, safety details
  22. Peltandra virginica (Green Arrow-arum) NC State Extension Gardener Plant ToolboxBacks up: safety, effort & ID risk, safety details
  23. Arrow Arum (Tuckahoe) (Education: Plants), archived copy of October 19, 2019 Jefferson Patterson Park & Museum (Maryland Historical Trust, the State Museum of Archaeology), via the Internet ArchiveBacks up: safety, effort & ID risk, safety details
  24. Saururus cernuus (Lizard’s Tail) NC State Extension Gardener Plant ToolboxBacks up: safety, effort & ID risk, safety details
  25. Sagittaria latifolia (Broad-leaved Arrowhead, Duck Potato) NC State Extension Gardener Plant ToolboxBacks up: safety, effort & ID risk, safety details
  26. Copper and lead uptake by aquatic macrophytes in eastern Connecticut, U.S.A. (Heisey & Damman, Aquatic Botany 14, 1982), abstract Penn State University research portal (Pure)Backs up: safety, safety details
  27. Reconstruction of Anacostia wetlands: success? (Hammerschlag and others), publication summary US Geological SurveyBacks up: safety, safety details
  28. Pickerelweed (aquatic plant ID and treatment) Virginia Department of Wildlife ResourcesBacks up: safety, safety details
  29. Plants at Kenilworth Aquatic Gardens National Park Service, Kenilworth Park & Aquatic GardensBacks up: season
  30. iNaturalist research-grade observations of Pontederia cordata within 25 km of Washington, DC, by month (annotated flowering) iNaturalistBacks up: season
  31. iNaturalist research-grade observations of Pontederia cordata within 25 km of Washington, DC, by month (all observations) iNaturalistBacks up: season
  32. Pickerel Weed (Green Deane) Eat The WeedsBacks up: season, description, uses, habitat, safety, keeping
  33. Pontederia cordata (Pickerelweed) NC State Extension Gardener Plant ToolboxBacks up: season, description, uses, habitat, safety, native or invasive status
  34. 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: uses, safety
  35. Pickerelweed | Pontederia cordata (P3735-31) Mississippi State University ExtensionBacks up: uses, safety, effort & ID risk, keeping, safety details