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A Forager’s Year

No. 170

Chinese yam

Dioscorea polystachya (syn. D. batatas; D. oppositifolia as misapplied in US usage)

cinnamon vine, Chinese potato

Roots, bulbs & tubers underground tuber (cooked)

Find
Common in the right habitat
Effort
Real work
ID risk
Careful
Origin
non-native ★★★
Safety marks
  • Toxic 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

A twining, deciduous vine of the yam family, native to China and brought to the United States as an ornamental, medicinal and food plant; it is now invasive (Plant Invaders of Mid-Atlantic Natural Areas). Its stems are thin and wiry and twine clockwise (left to right going upwards), and its leaves are heart- to arrow-shaped with a deeply lobed base and a tapering tip (Plant Invaders of Mid-Atlantic Natural Areas). New leaves have a reddish or bronze tint, and the leaf edges, leafstalks and stems can be tinged reddish purple (South Carolina Exotic Pest Plant Council; Eat The Weeds). It rarely flowers in the United States and spreads mainly by small, round, potato-like bulbils in the leaf axils and by large, elongated, yam-like underground tubers (Plant Invaders of Mid-Atlantic Natural Areas). NC State says the tuber grows 2 to 3 feet long. Eat The Weeds says a one-year-old root weighs about 3 ounces and a two-year-old root about a pound, that a root in good soil can reach five pounds, and that its flavor is between a sweet potato and a regular potato.

Safety

Cook the tuber. NC State rates the raw tuber’s poison severity as low: handling the uncooked tubers can irritate the skin, and eating them raw can cause irritation and burning of the mouth, lips, tongue and throat that usually lasts a few minutes; the cause is calcium oxalate crystals, and NC State says it is safest to cook the root. Eat The Weeds, a foraging site, also says: "The root should be cooked." The Botanical Dermatology Database says skin irritation from raw yam tubers may come from steroidal saponins, which washing or boiling removes, and a 2014 study in the Journal of Natural Medicines notes that some wild-growing yams are toxic and may cause vomiting and diarrhea if eaten raw or under-processed. An older field guide (Fernald and Kinsey, 1958) warns that the vigorous new shoots are purgative and should not be eaten; no modern source checked confirms or rules this out. Lookalikes: unlike native wild yam, the morning glories, field bindweed and saw greenbrier, Chinese yam has small, potato-like bulbils in the leaf axils, and its stems twine clockwise (Plant Invaders of Mid-Atlantic Natural Areas). Native wild yam has rounded heart-shaped leaves, stems that twine the other way and no bulbils (Plant Invaders of Mid-Atlantic Natural Areas), lacks the reddish new leaves (South Carolina Exotic Pest Plant Council) and grows from slender rhizomes; NC State says it does not produce edible tubers, and Memorial Sloan Kettering Cancer Center notes it caused chronic kidney injury in animal studies. Morning glories have showy funnel-shaped flowers and no bulbils (Plant Invaders of Mid-Atlantic Natural Areas): tall morning-glory and small white morning-glory, whose seeds NC State lists as poisonous (low severity), and the native wild potato vine, whose roots NC State says can be eaten cooked but are a purgative raw. Field bindweed has halberd-shaped leaves and white flowers and no bulbils (Plant Invaders of Mid-Atlantic Natural Areas) and contains alkaloids that are mildly toxic to some livestock (Nebraska Extension); Ohio State University finds no reports that it is poisonous to people. Saw greenbrier has thorns and blue to purple berries (Plant Invaders of Mid-Atlantic Natural Areas); its young shoots are edible (NC State), and it is not recorded near DC. Air potato, an invasive yam of the Deep South (NC State), twines the other way, has round, heart-shaped alternate leaves and larger bulbils (Eat The Weeds), and its tubers and bulbils may contain toxic compounds (Florida Museum of Natural History); the Virginia plant atlas lists no air potato in Virginia. Chinese yam is a listed invasive and a herbicide target: Plant Invaders of Mid-Atlantic Natural Areas says an herbicide may be effective for large infestations, and Montgomery Parks and Arlington County treat invasive plants in their parks with herbicide. Dig only where you know the patch has not been sprayed.

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
Look-alikes named by Plant Invaders of Mid-Atlantic Natural Areas, none with bulbils in the leaf axils, include native wild yam, which caused kidney injury in animal studies (Memorial Sloan Kettering Cancer Center), and morning glories, whose seeds are poisonous (NC State); wild yam also twines counterclockwise, lacks the reddish new leaves (South Carolina Exotic Pest Plant Council) and grows from slender rhizomes rather than a large tuber (NC State). The toxic air potato twines the other way and has round, alternate leaves (Eat The Weeds). Wild potato vine, field bindweed and saw greenbrier (not recorded near DC) are harmless look-alikes.
Handling hazards
Irritant sap/pulp (minor)
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.

Handling hazards: what this means

Stings, thorns, irritating or phototoxic sap, staining hulls and spiny husks, with a severity: minor = brief discomfort; moderate = rash or blisters lasting days; serious = burns, scarring or medical care possible.

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 Oct
Peak
early Nov–late Nov
Ends
late Mar

Eat The Weeds gives fall as this yam’s season and says the vine dies back in winter (in Florida, December through February), making the root hard to find unless the spot is marked. The South Carolina Exotic Pest Plant Council says the vines die back during winter, with the old vines left as trellises for the next year’s growth. No source gives digging dates for the DC area, so all three boundaries are estimates: dig from October, while the vines still show where the tubers are, until new growth starts in spring. Marking the vines in fall makes winter digging possible.

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 the dig for the DC area; early October starts the fall season Eat The Weeds gives, while the vines are still green and easy to find.

Peak

estimated: No source names a best month; November is the end of the fall season Eat The Weeds gives, when the vines are dying back but still mark where to dig.

End

estimated: No DC-area source gives an end; late March keeps the winter dig of marked plants and ends before the vines come back up in mid April.

Evidence

start: Eat The Weeds: 'TIME OF YEAR: Fall.' iNaturalist (DC, 25 km): research-grade sightings by week stay steady through early October (weeks 40-42: 14, 12 and 12). | peak: Eat The Weeds: 'TIME OF YEAR: Fall.' South Carolina Exotic Pest Plant Council: 'Vines die back during winter with old vines providing trellises for regrowth.' iNaturalist (DC, 25 km): weekly sightings fall from 9 in week 44 to 5, 2 and then 0 by week 47 (late November). | end: Eat The Weeds: 'In Florida vine dies December through February making locating difficult unless you mark it.' iNaturalist (DC, 25 km): no research-grade sightings from week 47 to week 15; sightings resume in mid April (weeks 16-17: 3 and 47).

Where to look

Moist woods, stream valleys, old fields and roadsides, logged most in Rock Creek Park, along the C&O Canal, in Glencarlyn Park, in Sligo Creek Stream Valley Park and in Barcroft Park, where digging is not allowed; dig only on private land with the owner’s permission.

Habitats
disturbed ground & waste places, old fields & meadows, floodplain & stream-valley forest
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)
  • Rock Creek Park

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

    Look but don’t pick: Rock Creek Park’s compendium bans gathering any fruit, nut, berry, seed or greenery.

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

    33 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.

  • Glencarlyn Park

    29 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.

  • Sligo Creek Stream Valley Park

    12 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.

  • Barcroft Park

    11 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

  • cooked like a potato, the most common use (Eat The Weeds)
  • peeled, then sliced or mashed and baked (Eat The Weeds)
  • cooked, chilled and used in a potato salad (Eat The Weeds)
  • harvest by digging out the whole long tuber, which can grow up to three feet long and weigh up to five pounds in good soil (Eat The Weeds)

Keeping

Keep cold and moist and use within a few weeks.

Use within
weeks
Keeps fresh
Keep the tubers cold and moist, for example in perforated plastic bags in the refrigerator, for a few weeks (general guidance for root vegetables). University of Minnesota: potatoes and root crops keep best dark, cold and moist (32–40°F, about 95% humidity); perforated plastic bags in the fridge give cold, moist conditions for a moderate time.
Keeping basis
general guidance for its type

Ways to keep it

  • Store whole as researched: root cellar; canning: n/a (not shelf-canned)

    University of Minnesota: root cellars provide cold and moist conditions; give them ventilation and protection from rodents (general guidance for root vegetables).

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

Synonyms checked: USDA PLANTS lists the US plant as Dioscorea oppositifolia (DIOP), introduced in the lower 48, and its symbol for D. batatas (DIBA2) leads to the same record; the Virginia plant atlas gives D. batatas as a synonym and calls the name D. oppositifolia misapplied; the Virginia DCR list (as cinnamon vine), the MISC list and Plant Invaders use D. polystachya.

Origin
non-native
Native range
central and southern China to the Kuril Islands and Taiwan (per NC State); China (Plant Invaders of Mid-Atlantic Natural Areas)
Invader credit
★★★
Virginia invasive rank
High
Maryland invasive status
Advisory (MISC list)
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 575 = 532 research-grade iNaturalist sightings within 25 km + 101 needs-ID sightings counted at 33% (532 of the 1,612 research-grade Dioscorea sightings here are Chinese yam) + 10 'cultivated' (planted) sightings (rule A); that is tier 2 by count (rule B). Final tier 2.
Effort
Real work Dig out the whole long tuber, which grows 2 to 3 feet long (NC State), then peel it and cook it like a potato (Eat The Weeds).
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

31 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. Virginia Invasive Plant Species List (effective date: September 2024) Virginia Department of Conservation and Recreation, Division of Natural HeritageBacks up: picking rules, native or invasive status
  4. 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: picking rules, native or invasive status
  5. Plant Invaders of Mid-Atlantic Natural Areas, Field Guide (Swearingen & Fulton, 2022), Chinese yam, pp. 158-159 Mid-Atlantic Invasive Plant Council / Passiflora Press (hosted by Bugwood/Mid-Atlantic Invaders Tool)Backs up: description, habitat, safety, picking rules, native or invasive status, effort & ID risk, safety details
  6. Dioscorea polystachya (Chinese Yam) NC State Extension Gardener Plant ToolboxBacks up: description, habitat, safety, native or invasive status
  7. iNaturalist research-grade observations of Dioscorea polystachya within 25 km of downtown DC iNaturalistBacks up: findability
  8. Dioscorea polystachya (Chinese Yam, Cinnamon Vine) (Digital Atlas of the Virginia Flora) Virginia Botanical Associates (Digital Atlas of the Virginia Flora)Backs up: habitat, native or invasive status, findability
  9. Harvesting and storing home garden vegetables University of Minnesota ExtensionBacks up: keeping
  10. USDA PLANTS Database: Dioscorea oppositifolia (DIOP), native status USDA NRCSBacks up: native or invasive status
  11. 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
  12. Invasive Plants in the District DC Department of Energy & EnvironmentBacks up: native or invasive status
  13. Convolvulus arvensis (Field Bindweed) NC State Extension Gardener Plant ToolboxBacks up: safety details
  14. Genera beginning with D (Digital Atlas of the Virginia Flora) Virginia Botanical Associates (Digital Atlas of the Virginia Flora)Backs up: safety, effort & ID risk, safety details
  15. Dioscoreaceae (Botanical Dermatology Database) Botanical Dermatology Database (BoDD)Backs up: safety, effort & ID risk, safety details
  16. Dioscorea villosa (Wild Yam) NC State Extension Gardener Plant ToolboxBacks up: safety, effort & ID risk, safety details
  17. Wild Yam (About Herbs, Botanicals & Other Products) Memorial Sloan Kettering Cancer CenterBacks up: safety, effort & ID risk, safety details
  18. Ipomoea purpurea (Common Morning Glory) NC State Extension Gardener Plant ToolboxBacks up: safety, effort & ID risk, safety details
  19. Ipomoea (Morning Glory), genus page NC State Extension Gardener Plant ToolboxBacks up: safety, effort & ID risk, safety details
  20. Ipomoea pandurata (Wild Potato Vine) NC State Extension Gardener Plant ToolboxBacks up: safety, effort & ID risk, safety details
  21. Field bindweed, Convolvulus arvensis (Ohio Perennial and Biennial Weed Guide) The Ohio State University (Ohio Perennial and Biennial Weed Guide)Backs up: safety, effort & ID risk, safety details
  22. Smilax bona-nox (Saw Greenbrier) NC State Extension Gardener Plant ToolboxBacks up: safety, effort & ID risk, safety details
  23. Dioscorea bulbifera (Air Potato) NC State Extension Gardener Plant ToolboxBacks up: safety, effort & ID risk, safety details
  24. Five facts: Air potatoes in Florida Florida Museum of Natural History (University of Florida)Backs up: safety, effort & ID risk, safety details
  25. Application of anatomy and HPTLC in characterizing species of Dioscorea (Dioscoreaceae) (Raman et al., J Nat Med 2014) Journal of Natural Medicines (author manuscript in PubMed Central, National Library of Medicine)Backs up: safety, safety details
  26. Field Bindweed (BeefWatch, 2020) Nebraska Extension (University of Nebraska-Lincoln)Backs up: safety, safety details
  27. Pesticide use and notification (park treatment schedule) Montgomery Parks (M-NCPPC)Backs up: safety, safety details
  28. Budget guidance: invasive plants (Arlington County Park and Recreation Commission, November 2025) Arlington County, VirginiaBacks up: safety, safety details
  29. iNaturalist research-grade observations of Dioscorea polystachya within 25 km of Washington, DC, by week (all observations) iNaturalistBacks up: season
  30. Green Gone Bad: Featured Ornamental Plant: Dioscorea polystachya (Chinese Yam) South Carolina Exotic Pest Plant Council (SE-EPPC)Backs up: season, description, habitat, safety, picking rules, effort & ID risk, safety details
  31. Yam C, the Chinese (Green Deane) Eat The WeedsBacks up: season, description, uses, habitat, safety