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A Forager’s Year

No. 13

Curly dock

Rumex crispus

Leaves & tender stems young, tightly curled leaves (and early spring stalks)

Drawing: Britton & Brown, Illustrated Flora (1913)

Find
Common in the right habitat
Effort
Quick kitchen prep
ID risk
Beginner
Origin
non-native ★
Safety marks
  • Spray risk
Uses
  • Eat raw / salad
  • 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

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. 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

A taprooted perennial forming a rosette of long, lance-shaped leaves with distinctly wavy, crisped margins. From spring into early summer it sends up a tall stalk of greenish flowers that turn into dark brown seed clusters. Young leaves are tart; older leaves are bitter.

Safety

High in oxalic acid: don’t overindulge; can irritate the urinary tract and raise kidney-stone risk. Older leaves are bitter.

Safety flags

  • Eat in moderation

    oxalic acid: Don’t overindulge; too much can irritate the urinary tract and raise kidney-stone risk, and people with kidney problems should probably avoid it.

  • Spray risk

    University of Maryland Extension lists it as a lawn weed and recommends spot-treating it with a selective broadleaf herbicide (2,4-D, MCPP, dicamba or triclopyr), so treated lawns, sports fields and park turf are likely. Virginia DCR also lists curly dock as a low-rank invasive.

Safety marks and flags: what this means

Deadly lookalike / Toxic lookalike: a cited source names a lookalike of that danger. 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
Beginner
Why
No toxic lookalike is named in the sources.
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

Window 1

Starts
early Mar
Peak
late Mar–late Mar
Ends
late Apr

Window 2

Starts
early Oct
Peak
–
Ends
late Nov

Two windows. Spring (early Mar to late Apr) is the main season: pick only young leaves still curled in the center of the rosette, before the flower stalk rises; curly dock blooms from April (Missouri Dept. of Conservation), and one DC iNaturalist record already shows a seed head in late April. Older leaves are bitter. Fall (early Oct to late Nov): rosettes can be picked again, but no source describes this as a main harvest, so treat it as a minor second chance.

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 (window 1), peak (window 1), end (window 1), start (window 2), end (window 2)

Window 1: Start

estimated: No regional source gives a start date.

Window 1: Peak

estimated: Peak placed before flower stalks rise; no source gives a month.

Window 1: End

estimated: End moved from mid Apr to late Apr to cover the Missouri book’s March-April collection; by late April most plants are sending up flower stalks, so pick only curled center leaves.

Window 1: Evidence

start: Missouri book: dock shoots March-April. DC iNaturalist curly dock records by third of the month (days 1-10, 11-20, 21-end): 1 in mid February, then 3 in early March, none in mid March and 3 in late March, as rosettes become noticeable. | peak: MDC: young, tender, early-season leaves are the ones eaten. | end: MDC: blooms April-June. Missouri book: shoots March-April; dock flowers April-May. DC iNaturalist: first flowering and fruiting annotations in late April.

Window 2: Start

estimated: No source describes a fall leaf flush; the window reflects rosettes still present in fall.

Window 2: Peak

Window 2: End

estimated: End set at late November; no source gives a date.

Window 2: Evidence

start: DC iNaturalist: 15 records in September, 12 in October, 5 in November. | peak: Few fall records. | end: DC records drop to 5 in November and 2 in December.

Where to look

Old fields, ditches and waste ground, logged most along Four Mile Run, at Dyke Marsh and on the Mount Vernon Trail (no picking); look in private fields and ditches with permission.

Habitats
disturbed ground & waste places, old fields & meadows
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)
  • Mount Vernon Trail

    29 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.

  • Four Mile Run stream valley (Arlington/Alexandria)

    20 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.

  • Dyke Marsh Wildlife Preserve

    9 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

    9 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.

  • Huntley Meadows Park

    9 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.

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 (rugosa rose) have no places. No most-logged places are named for at-risk plants (ramps, chinquapin, American chestnut); chinquapin’s page names Mason Neck State Park, where picking is legal, and asks you to leave most nuts. 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

  • cooked as a potherb (several changes of water)
  • small amounts raw in mixed salads
  • in a mess of mixed spring greens

Keeping

Cook within a few days; freeze surplus once cooked or blanched.

Use within
within a few days
Keeps fresh
2–4 days refrigerated in a perforated bag (general guidance for leafy greens).
Keeping basis
general guidance for its type

Ways to keep it

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

    Cook it the usual way (several changes of water), then cool and freeze in portions; or use the standard 2-minute blanch. NCHFP: water-blanch 2 minutes (collards 3), cool, drain, pack with 1/2-inch headspace. Frozen greens are for cooked dishes only. Greens are low-acid and may only be pressure-canned, never water-bath canned, so freezing is the practical home method.

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

VA DCR lists it as 'Rumex crispus ssp. crispus' (the widespread weedy subspecies).

Origin
non-native
Native range
Eurasia & Africa
Invader credit
★
Virginia invasive rank
Low
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 657 = 415 research-grade iNaturalist sightings within 25 km + 575 needs-ID sightings counted at 40% (415 of the 1,030 research-grade Rumex sightings here are curly dock) + 10 'cultivated' (planted) sightings (rule A); that is tier 2 by count (rule B). Final tier 2.
Effort
Quick kitchen prep Cook young curled leaves as a potherb, changing the water once or twice; raw use is limited to small amounts.
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

18 sources, each linked to the original.

  1. Rock Creek Park Superintendent’s Compendium National Park ServiceBacks up: picking rules
  2. Rumex crispus (Curly Dock) NC State Extension Gardener Plant ToolboxBacks up: description, safety, habitat, native or invasive status
  3. iNaturalist research-grade observations of Rumex crispus within 25 km of downtown DC iNaturalistBacks up: findability
  4. Bulletin #4180, Vegetables and Fruits for Health: Greens University of Maine Cooperative ExtensionBacks up: keeping
  5. Freezing Greens (Including Spinach) National Center for Home Food Preservation (University of Georgia)Backs up: keeping
  6. Blanching Vegetables National Center for Home Food Preservation (University of Georgia)Backs up: keeping
  7. Got the Wintertime “Greens”? National Center for Home Food Preservation (University of Georgia)Backs up: keeping
  8. USDA PLANTS Database: Rumex crispus (RUCR), native status USDA NRCSBacks up: native or invasive status
  9. 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
  10. 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
  11. 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
  12. Invasive Plants in the District DC Department of Energy & EnvironmentBacks up: native or invasive status
  13. Virginia Invasive Plant Species List (effective date: September 2024) Virginia Department of Conservation and Recreation, Division of Natural HeritageBacks up: native or invasive status, safety details
  14. Dock University of Maryland ExtensionBacks up: safety details
  15. Research-grade observations of curly dock (Rumex crispus) within 25 km of DC, by month (all observations) iNaturalistBacks up: season
  16. Research-grade observations of curly dock (Rumex crispus) within 25 km of DC, by month (fruiting) iNaturalistBacks up: season
  17. Wild Edibles of Missouri (Jan Phillips, 2nd ed.) Missouri Department of ConservationBacks up: season, uses, safety
  18. Curly Dock (field guide) Missouri Department of ConservationBacks up: season, uses, safety, habitat, description