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A Forager’s Year

No. 155

Yellow nutsedge

Cyperus esculentus

chufa, tiger nut, earth almond

Roots, bulbs & tubers tubers (small underground "nuts")

Drawing: Britton & Brown, Illustrated Flora (1913)

Find
Patchy
Effort
Real work
ID risk
Beginner
Origin
native
Safety marks
  • Spray risk
Uses
  • Eat raw / salad
  • Cooked vegetable / soup
  • Juice & drinks
  • Coffee substitute

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

A grass-like sedge with shiny, yellowish-green leaves, a triangular stem and a golden-brown flower head (Ohio State). Thin underground runners end in single tubers, the "nuts" (UC IPM; Cornell). Mature tubers are hard, round and brown to black, about 1/8 to 3/4 inch across (Cornell). The Virginia plant atlas calls the tubers small, but Cornell reports an average tuber weight of 700 milligrams in Maryland, against 70 in Minnesota and 150 in Illinois. They have a nut-like flavor, often compared to almonds, but are rather chewy with a tough skin (NC State; UC IPM; Ohio State). The cultivated chufa or tiger nut, long a food around the Mediterranean, is a variety of the same species (Cornell).

Safety

No toxicity is reported for yellow nutsedge in the sources checked, and the tubers can be eaten raw (NC State). The lookalike the sources name for the tubers is purple nutsedge, which is also edible but bitter (NC State; UC IPM). Purple nutsedge has darker green leaves with rounded tips and red-brown to purple flower clusters, and its tubers grow in chains along the runners, while yellow nutsedge forms a single tuber at the tip of each runner (Ohio State; Oregon State University; UC IPM). Purple nutsedge is infrequent in Virginia, where it grows in the southern and central Coastal Plain (Virginia plant atlas). Green kyllinga, a lawn sedge often confused with nutsedge, forms no tubers (UC IPM). Extension services advise spot-treating yellow nutsedge in lawns with herbicides such as halosulfuron (University of Maryland Extension; Penn State), and Oregon State University advises eating nutsedge tubers only from your own property and never from plants that have been sprayed or that grow on roadsides. A few cases of allergy to tiger nuts have been reported, in people with pollen allergies (Journal of Investigational Allergology and Clinical Immunology, 2013).

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
Beginner
Why
No toxic lookalike is named. Purple nutsedge, the only close lookalike, is also edible but bitter (NC State; UC IPM); it has darker leaves with rounded tips, purplish flower clusters and tubers in chains, while yellow nutsedge has one tuber at the tip of each runner (Ohio State; Oregon State University). Green kyllinga forms no tubers (UC IPM). The triangular stem separates nutsedges from young grasses (Ohio State).
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
late Aug
Peak
early Oct–late Oct
Ends
mid Nov

Window 2

Starts
early Mar
Peak
–
Ends
late Apr

In most of Pennsylvania the tubers begin to form at the tips of the runners in late June or early July and begin to mature in mid to late summer (Penn State). Tuber formation continues through the rest of the growing season (Ohio State), and the leaves die back after the first hard frost (Penn State). The tubers stay dormant in the soil over winter and sprout the following spring (Ohio State; Cornell), so a patch you know can also be dug in early spring before it sprouts. Fernald and Kinsey (1958) give the season as late autumn or early spring, the tubers keeping over winter. No source gives digging dates for the DC area.

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

Window 1: Start

sourced

Window 1: Peak

estimated: No source names a best month; October is late in the tuber-forming season that Ohio State and eOrganic describe, when the most tubers have formed, and before the first hard frost kills the leaves that mark the patch (Penn State).

Window 1: End

estimated: No source gives an end date for the DC area; mid November is about when the first hard frost kills the leaves, after which the patch is hard to find. The tubers themselves stay in the ground (second window).

Window 1: Evidence

start: Penn State (Pennsylvania): 'In most of Pennsylvania, tubers begin to form at the tips of rhizomes in late June or early July.' Herbicides work best 'before tubers begin to mature in mid to late summer'. Ohio State: 'Tuber formation begins in late July and continues through the rest of the growing season.' Cornell: 'tuber formation, which occurs primarily in late summer and fall'. | peak: Ohio State: 'Tuber formation begins in late July and continues through the rest of the growing season.' eOrganic: 'In temperate latitudes, tuber formation is triggered by shortening daylength in late summer and accelerates while aboveground growth rates decline'. Penn State: 'The foliage of yellow nutsedge dies back in the fall following the first hard frost.' | end: Penn State: 'The foliage of yellow nutsedge dies back in the fall following the first hard frost.' Ohio State: 'All foliage, rhizomes, roots and basal bulbs die with the first hard frost.' eOrganic: 'Foliage dies back with the first fall frost, and the weed overwinters as dormant tubers.' iNaturalist (25 km, research grade): 4 sightings in October, 1 in November, none December to May.

Window 2: Start

estimated: No source dates a spring dig; early March is when the ground has usually thawed. Cornell says tubers near the surface may be killed by hard winter freezes, so the winter months are left out.

Window 2: Peak

Window 2: End

estimated: Late April keeps the dig before the tubers sprout, which Ohio State puts at soil temperatures near 54°F, in May; a sprouting tuber spends its stored food on the new shoot (UC IPM).

Window 2: Evidence

start: Ohio State: 'Tubers remain dormant over the winter, and many germinate the following spring.' Cornell: 'The tubers are dormant when produced and usually sprout the following spring.' Penn State: 'Rhizomes and tubers can also serve as overwintering structures.' Fernald and Kinsey (1958): 'late autumn or early spring, the tubers keeping over winter'. | end: Ohio State: 'Tuber germination typically begins as soil temperatures reach about 54 Farenheit degree (12 Celsius) (in May)'.

Where to look

Lawns, gardens and other moist, open ground, especially poorly drained spots. iNaturalist sightings are few and scattered: two each on Glenstone Museum’s private grounds, at Kenilworth Park & Aquatic Gardens and along the Mount Vernon Trail, and digging is not allowed at Kenilworth or on the Mount Vernon Trail. Roots may not be dug in any listed park, so dig only on private land with the owner’s permission, such as your own unsprayed yard or garden.

Habitats
lawns & sidewalk cracks, disturbed ground & waste places, old fields & meadows, 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 (3 places)
  • Glenstone Museum grounds (private)

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

    Private property: pick only with the owner’s permission.

  • Kenilworth Park & Aquatic Gardens

    2 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.

  • Mount Vernon Trail

    2 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.

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 right out of the ground, boiled or roasted (Eat The Weeds; NC State)
  • dried and ground into a powder for confectionery (NC State)
  • a sweet drink made from the ground tubers with water, cinnamon, sugar, vanilla and ice (NC State), like the Spanish horchata de chufa (Cornell)
  • roasted as a coffee substitute (NC State)
  • soak hard tubers in water to soften them, and rub them to loosen the husk (Eat The Weeds)

Keeping

Keep cold and moist and use within a few weeks, or dry them for longer storage.

Use within
weeks
Keeps fresh
Keep fresh tubers cold and moist, for example in perforated plastic bags in the refrigerator (general guidance for root vegetables; University of Minnesota).
Keeping basis
general guidance for its type

Ways to keep it

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

    NC State says the tubers can be dried and ground into a powder. Dry them until brittle and store them in a cool, dry, dark place; NCHFP gives 4 months to 1 year for dried foods, with vegetables keeping about half as long as fruits (general guidance for dried foods). Soak hard, dried tubers in water to soften them (Eat The Weeds).

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

USDA PLANTS lists yellow nutsedge as both native and introduced in the lower 48; Cornell says weedy races in the U.S. may be introduced, and the Virginia plant atlas and University of Maryland Extension call its nativity to the area uncertain. The cultivated chufa is a variety of the same species (Cornell). Not on the VA DCR or MDA lists; the MISC list names only non-native Cyperus species.

Origin
native
Native range
North and South America, southern Europe and Africa (per Cornell); NC State gives the southern United States and tropical to subtropical regions
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
Patchy Estimate 116 = 76 research-grade iNaturalist sightings within 25 km + 161 needs-ID sightings counted at 21% (76 of the 363 research-grade Cyperus sightings here are yellow nutsedge) + 6 'cultivated' (planted) sightings (rule A); that is tier 3 by count (rule B). Final tier 3.
Effort
Real work Dig up the patch, sift the small tubers out of the soil one by one, wash them and rub off the husk, then eat them raw, boiled or roasted; hard, dried tubers need soaking first, and grinding them for flour or a drink is also 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

26 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. Yellow Nutsedge (Cyperus esculentus), Ohio Perennial & Biennial Weed Guide The Ohio State University (CFAES, Ohio Agricultural Research and Development Center)Backs up: description, safety, season, habitat
  4. Pest Notes: Nutsedge (Publication 7432) University of California Statewide IPM Program (UC IPM)Backs up: description, safety, effort & ID risk
  5. Cyperus esculentus (Yellow Nutsedge, Chufa, Tiger Nut) NC State Extension Gardener Plant ToolboxBacks up: description, uses, safety, habitat, season, native or invasive status, keeping
  6. Yellow nutsedge, Cyperus esculentus (Weed Profiles) Cornell University College of Agriculture and Life Sciences, Weed ScienceBacks up: description, uses, safety, season, habitat, native or invasive status
  7. iNaturalist research-grade observations of Cyperus esculentus within 25 km of downtown DC iNaturalistBacks up: findability
  8. Got Nutsedge? Find the Nutlets Fairfax County Master Gardeners AssociationBacks up: habitat
  9. Cyperus esculentus L. var. leptostachyus Böckler (Digital Atlas of the Virginia Flora) Virginia Botanical Associates (Digital Atlas of the Virginia Flora)Backs up: habitat, description, native or invasive status
  10. Yellow Nutsedge (Weed Identification, Lawn Weeds) University of Maryland Extension, Home and Garden Information CenterBacks up: habitat, safety, native or invasive status
  11. Harvesting and storing home garden vegetables University of Minnesota ExtensionBacks up: keeping
  12. Packaging and Storing Dried Foods National Center for Home Food Preservation (University of Georgia)Backs up: keeping
  13. USDA PLANTS Database: Cyperus esculentus (CYES), native status USDA NRCSBacks up: native or invasive status
  14. Virginia Invasive Plant Species List (effective date: September 2024) Virginia Department of Conservation and Recreation, Division of Natural HeritageBacks up: native or invasive status
  15. 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
  16. 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
  17. 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
  18. Invasive Plants in the District DC Department of Energy & EnvironmentBacks up: native or invasive status
  19. Cyperus rotundus (Purple Nutsedge) NC State Extension Gardener Plant ToolboxBacks up: safety, effort & ID risk, safety details
  20. Pollen-Food Syndrome Involving Allergy to Tiger Nut (González-de-Olano et al., J Investig Allergol Clin Immunol 2013;23(3):197-198) Journal of Investigational Allergology and Clinical ImmunologyBacks up: safety, effort & ID risk, safety details
  21. Nutsedge (Solve Pest Problems) Oregon State University Extension ServiceBacks up: safety, safety details
  22. Cyperus rotundus L. (Digital Atlas of the Virginia Flora) Virginia Botanical Associates (Digital Atlas of the Virginia Flora)Backs up: safety, safety details
  23. iNaturalist research-grade observations of Cyperus esculentus within 25 km of Washington, DC, by month (all observations) iNaturalistBacks up: season
  24. Lawn and Turfgrass Weeds: Yellow Nutsedge (Cyperus esculentus) Penn State ExtensionBacks up: season, habitat, safety
  25. Weed Profile: Yellow Nutsedge (Cyperus esculentus) and Purple Nutsedge (C. rotundus) eOrganic (Cooperative Extension)Backs up: season, safety
  26. Cyperus Esculentus & Rotundus For Lunch (Green Deane) Eat The WeedsBacks up: uses, habitat, keeping