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A Forager’s Year

No. 162

Pecan

Carya illinoinensis

pecan hickory, sweet pecan

Nut & seed nuts

Drawing: Britton & Brown, Illustrated Flora (1913)

Find
Elusive
Effort
Quick kitchen prep
ID risk
Beginner
Origin
native
Uses
  • Eat raw / salad
  • Baking & desserts
  • 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: At least one park allows it. 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.

Seasons

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

What it looks like

The largest of the hickories (NC State; Lady Bird Johnson Wildflower Center), a tall tree with gray-brown, furrowed bark and long compound leaves of 9 to 17 narrow, toothed leaflets that may be curved (NC State; USDA Forest Service). Each nut grows inside a thin husk that turns from green to brown or black as it ripens, then splits into four sections all the way to the base and releases the nut (USDA Forest Service; Woody Plant Seed Manual); empty husks often stay on the tree for weeks after the nuts fall (Lady Bird Johnson Wildflower Center). The nut is oval to oblong, 1 to 3 inches long, tan to brown with darker streaks, and thin-shelled (NC State; Lady Bird Johnson Wildflower Center; USDA Forest Service); Medsger (1939) describes it as smooth and pointed. The kernels are sweet; Medsger (1939) called them perhaps the best of all the hickory nuts. Northern pecans, the hardy kind, have smaller nuts with thicker shells than southern pecans but a richer flavor (Virginia Cooperative Extension). Crops are lighter and less reliable toward the northern edge of where pecans grow (NC State; Lady Bird Johnson Wildflower Center).

Safety

No toxicity is reported in the sources checked (NC State; USDA Forest Service). Lookalike: bitternut hickory (C. cordiformis, also called bitter pecan) has kernels of extreme bitterness and astringency that the Silvics Manual says are of little value for human consumption; it is not described as dangerous. Tell it apart by its sulfur-yellow buds and its husk, which splits only to about the middle and clings to the nut, while a pecan husk splits to the base and releases the nut (Keystone Tree Crops Cooperative; USDA Woody Plant Seed Manual). NC State lists black walnut among trees often confused with pecan; its nuts are edible too, and pecan has fewer and longer leaflets. NC State also lists green ash, Chinese pistache and European mountain ash as trees confused with pecan; none of them bears a husked nut, and European mountain ash is not recorded near DC. Green ash has a dry, winged seed, Chinese pistache has small red-to-blue fruits that NC State calls inedible, and European mountain ash has small red-orange, berry-like fruits (NC State). Tree-nut allergy: pecan is one of the tree nuts named as a major food allergen in federal labeling law (FDA).

Lookalikes

  • Bitternut hickory (bitter pecan) Carya cordiformis harmless (may be edible)

    Bitternut is the hickory with sulfur-yellow buds that often come to a point; its thin husk, in four ridged sections that come to a pointed tip, stays on the nut after it drops, and the thin-shelled nut is the size of a nickel to a half dollar and bitter tasting (Keystone Tree Crops Cooperative’s harvester’s handbook). A pecan husk splits to the base and usually releases the nut, while a bitternut husk splits only to about the middle and clings (USDA Woody Plant Seed Manual). The Silvics Manual says bitternut kernels are of little value for human consumption because of their extreme bitterness and astringency; they are not described as dangerous.

  • Black walnut Juglans nigra harmless (may be edible)

    NC State lists black walnut among trees often confused with pecan; pecan has fewer and longer leaflets, and its husk splits into four sections when ripe (NC State). Black walnuts are edible nuts in their own right (USDA Forest Service).

  • Green ash Fraxinus pennsylvanica harmless (may be edible)

    NC State lists green ash among trees often confused with pecan. Green ash has opposite leaves with 5 to 9 leaflets, while pecan’s leaves are alternate with 9 to 17 leaflets, and its fruit is a single-winged, dry, flat samara, not a husked nut (NC State). NC State lists no poisonous part of green ash.

  • Chinese pistache Pistacia chinensis harmless (may be edible)

    NC State lists Chinese pistache among trees often confused with pecan. Its compound leaves have 10 to 12 leaflets with smooth edges, while pecan’s leaflets are toothed, and its fruits are round drupes about 1/4 inch across, red ripening to blue, which NC State calls inedible. NC State lists no poisonous part of Chinese pistache.

  • European mountain ash (not recorded near DC) Sorbus aucuparia harmless (may be edible)

    NC State lists European mountain ash among trees often confused with pecan. Its fruits are small, bright red-orange, berry-like pomes about 1/3 inch across, not husked nuts, and NC State says the fruit is processed into an alcoholic drink, juice and vinegar. It is not recorded near DC.

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. Bitternut hickory (bitter pecan) has bitter, astringent kernels but is not described as dangerous; its husk splits only partway and clings to the nut, while a pecan husk splits to the base. Black walnut, sometimes confused with pecan, is also edible. NC State’s other trees confused with pecan (green ash, Chinese pistache and European mountain ash) bear no husked nut.
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
late Sep
Peak
mid Oct–early Nov
Ends
late Nov

Pecans ripen in September and October and keep falling into December across the tree’s range (USDA Forest Service Silvics Manual and Fire Effects Information System; Woody Plant Seed Manual). In North Carolina they are typically harvested from the end of September through November, depending on the variety (NC State Extension). The nuts are ready when the husk turns brown and splits open (Washington State University Extension; NC State Extension). The late-September start, the mid-October to early-November peak and the late-November end are estimates. Pick up fallen nuts every other day, before squirrels and other wildlife get to them or they mold (NC State Extension). Crops vary: good crops come every 1 to 3 years (Silvics Manual), and late frosts can reduce nut production (NC State).

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 DC-area or Mid-Atlantic source with dates was found. Late September is the earliest harvest in the nearest regional source (North Carolina) and fits the range-wide September-October ripening. The DC iNaturalist records of ripe nuts (3 with a fruiting annotation in fall) date from Oct 18 to Nov 2, so local nuts may start later than late September.

Peak

estimated: No source names a peak. Mid October to early November spans the only dated local records of ripe nuts and the middle of the September-November collecting window.

End

estimated: Collecting sources end in November; the December seedfall in Silvics and FEIS is range-wide and not described as worth gathering, and fallen nuts are quickly taken by wildlife or mold. No DC record of ripe nuts after Nov 2.

Evidence

start: Silvics Manual (range-wide): 'Fruits ripen in September and October and are dispersed from September through December'. FEIS: 'The nuts mature from September to October'. Woody Plant Seed Manual table: pecan fruit ripening Sept-Oct. NC State Extension, Scotland County (North Carolina, south of the region): 'Pecans are typically harvested from the end of September through November and is dependent on variety.' | peak: iNaturalist fruiting-annotated sightings within 25 km of DC in fall: Oct 18 (2023, needs ID), Oct 25 (2021) and Nov 2 (2025). Lady Bird Johnson Wildflower Center: 'Collect nuts from September to November.' | end: NC State Extension, Scotland County: harvested 'from the end of September through November'. Lady Bird Johnson Wildflower Center: 'Collect nuts from September to November.' Silvics: dispersed 'from September through December'; FEIS: 'seedfall begins in September and ends in December'. NC State Extension: nuts should be picked up every other day 'to prevent the nuts from molding or being destroyed or removed by pests.'

Where to look

Planted around older homes and farmsteads and now and then along DC streets, sometimes escaping to woods edges and floodplains; logged most at Patuxent Research Refuge and on the University of Maryland campus, where picking rules were not checked. The C&O Canal (1 bushel a day) and Prince William Forest Park allow hickory nuts, which covers pecan, and Virginia state parks allow edible nuts, but no pecans are logged in any of them. Most trees are on private land, so ask the owner.

Habitats
street & yard trees (planted), woods edges, trailsides & thickets, 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.

Ask first: rules unclear or not checked

  • Patuxent Research Refuge

    2 sightings · Legal to pick: unknown · see them on iNaturalist

    Picking rules not checked. A federal facility, so ask before picking anything.

  • University of Maryland, College Park campus

    2 sightings · Legal to pick: unknown · see them on iNaturalist

    Picking rules not checked.

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

  • Eat raw: the kernels are sweet (NC State), and Medsger (1939) called them delicious, perhaps the best of all the hickory nuts
  • Add to breads, cookies, candies and fruit dishes (Washington State University Extension); pecans are used extensively in candies and cookies (USDA Forest Service)
  • Pecan pie, or mashed sweet potatoes with a pecan topping (NC State Extension)
  • Roasted: spread shelled nuts on a pan and heat at 350°F for 5 to 12 minutes, stirring occasionally, until lightly browned (Washington State University Extension)
  • Gather fallen nuts once the husks open and the nuts drop, every other day if you can, before squirrels and other wildlife get to them or the nuts mold; nuts that are loosening can be knocked down with a long pole (NC State Extension; Washington State University Extension)
  • Harvest tip: throw out nuts with holes in the shell (NC State Extension), and discard any that float when the nuts are put in water (Washington State University Extension)

Keeping

Dry them in the shell soon after gathering; they keep for months in a dry spot indoors, about a year at 32°F and years frozen.

Use within
months+
Keeps fresh
Dry the nuts in the shell after gathering, for example in porous burlap bags somewhere warm and airy (NC State Extension). Dried pecans keep several months in a dry spot indoors, about a year at 32°F, and several years in a freezer (NC State Extension). Shelled nutmeats must be refrigerated or frozen (Washington State University Extension).
Keeping basis
specific to this plant

Ways to keep it

  • Dry as researched: roast & store; canning: n/a (not shelf-canned)

    Roasted nuts keep less well than dried ones; eat them within 2 to 3 weeks (Washington State University Extension).

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

    For longer storage keep the nuts in a freezer, where they last several years (NC State Extension).

  • Store whole as researched: store in shell; canning: n/a (not shelf-canned)

    Dry in the shell, then keep in a cool, dry spot indoors for several months, or at 32°F for about a year (NC State Extension).

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 pecan as native in the lower 48 states, but its native range is the lower Mississippi Valley and nearby (USDA Forest Service); the Digital Atlas of the Virginia Flora treats it as introduced in Virginia, where it is cultivated and occasionally escapes.

Origin
native
Native range
central and east-central United States to Mexico (mainly the lower Mississippi Valley)
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
Elusive Estimate 43 = 11 research-grade iNaturalist sightings within 25 km + 56 needs-ID sightings counted at 2% (in the October 5 genus count, 11 of the 713 research-grade Carya sightings here were pecan) + 31 'cultivated' (planted) sightings (rule A); that is tier 4 by count (rule B). Rule D does not apply: the Digital Atlas of the Virginia Flora calls pecan "Infrequent, Coastal Plain and Piedmont" in Virginia, which is not a statement that it is rare or very infrequent, and the Lady Bird Johnson Wildflower Center’s note that "The tree does not bear liberal quantities of fruit in the northern part of its range" describes light crops, not wild trees that rarely bear. Final tier 4.
Effort
Quick kitchen prep Gather fallen nuts, crack the thin shells and pick out the kernels by hand; northern pecans have thicker shells and are harder to pick out.
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

33 sources, each linked to the original.

  1. Rock Creek Park Superintendent’s Compendium (2026) National Park ServiceBacks up: picking rules
  2. C&O Canal NHP Superintendent’s Compendium, effective September 11, 2026 National Park Service, Chesapeake and Ohio Canal NHPBacks up: picking rules
  3. Prince William Forest Park Superintendent’s Compendium (approved May 29, 2026) National Park ServiceBacks 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. Maryland man fined $50 for picking berries ReasonBacks up: picking rules
  6. 4VAC5-30-50. Flowers, plants, minerals, etc. Virginia Law Library (law.lis.virginia.gov)Backs up: picking rules
  7. Specialty Crops Profile: Introduction to Walnuts, Pecans and Other Nut Crops (Tony Bratsch) Virginia Cooperative Extension (Virginia Tech)Backs up: description, habitat
  8. Carya illinoinensis (Hardy Pecan, Pecan) NC State Extension Gardener Plant ToolboxBacks up: description, uses, safety, native or invasive status
  9. iNaturalist research-grade observations of Carya illinoinensis within 25 km of downtown DC iNaturalistBacks up: findability
  10. UFA Street Trees (DC Urban Forestry street-tree inventory), Carya illinoinensis records District of Columbia (DDOT Urban Forestry Division, via DC GIS)Backs up: habitat
  11. Carya illinoinensis (Pecan) Digital Atlas of the Virginia Flora, Virginia Botanical AssociatesBacks up: habitat, findability, native or invasive status
  12. USDA PLANTS Database: Carya illinoinensis (CAIL2), native status USDA NRCSBacks 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
  14. 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
  15. 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
  16. 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
  17. Invasive Plants in the District DC Department of Energy & EnvironmentBacks up: native or invasive status
  18. Guidance for Industry: Questions and Answers Regarding Food Allergen Labeling (Edition 5), January 2025 U.S. Food and Drug AdministrationBacks up: safety
  19. Bitternut hickory (Silvics of North America) USDA Forest ServiceBacks up: safety
  20. Carya cordiformis (Bitternut Hickory) NC State Extension Gardener Plant ToolboxBacks up: safety
  21. Yellowbud Hickory Harvester’s Handbook Keystone Tree Crops Cooperative (KTCC)Backs up: safety
  22. Black walnut (Silvics of North America) USDA Forest ServiceBacks up: safety details
  23. Fraxinus pennsylvanica (Green Ash, Red Ash) NC State Extension Gardener Plant ToolboxBacks up: safety, safety details
  24. Pistacia chinensis (Chinese Pistache) NC State Extension Gardener Plant ToolboxBacks up: safety, safety details
  25. Sorbus aucuparia (European Mountain Ash) NC State Extension Gardener Plant ToolboxBacks up: safety, safety details
  26. Pecan research-grade observations within 25 km of DC, by month (fruiting annotation) iNaturalistBacks up: season
  27. Carya illinoinensis (Pecan) Lady Bird Johnson Wildflower Center, University of Texas at AustinBacks up: season, description, habitat, findability
  28. Pecan (Silvics of North America) USDA Forest ServiceBacks up: season, description, habitat, safety, native or invasive status
  29. Carya, hickory (Woody Plant Seed Manual, Agriculture Handbook 727) USDA Forest ServiceBacks up: season, description, safety
  30. Pecans - A Southern Tradition (Oct. 31, 2022) NC State Extension, Scotland County CenterBacks up: season, uses, habitat, storage, keeping
  31. Carya illinoinensis (Fire Effects Information System) USDA Forest ServiceBacks up: season, uses, safety
  32. Growing Pecans in North Carolina NC State ExtensionBacks up: season, uses, storage, keeping
  33. Food Safety and Preservation: Nuts & Seeds Washington State University Extension, Lewis CountyBacks up: season, uses, storage, keeping