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A Forager’s Year

No. 125

European cranberrybush

Viburnum opulus (including var. americanum)

guelder rose, highbush cranberry, American cranberrybush

Fruit ripe drupes (cooked)

Drawing: Britton & Brown, Illustrated Flora (1913)

Find
Patchy
Effort
Quick kitchen prep
ID risk
Beginner
Origin
mixed ☆
Safety marks
  • Cook first
Uses
  • Pesto & sauces
  • Baking & desserts
  • Jam & jelly
  • Syrup & cordial
  • Juice & drinks
  • Wine & spirits

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.

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 shrub 8 to 16 feet tall (NC State) with opposite, three-lobed, coarsely toothed, maple-like leaves 2 to 4 inches long (Virginia Tech; USDA). Flat-topped clusters of white flowers in spring have a ring of large, sterile flowers around small fertile ones (USDA; NC State). They are followed by bright red, round, berry-like drupes about 1/4 to 1/3 inch across, each with a single, strongly flattened stone (USDA; Virginia Tech); the fruit hangs on into winter and shrivels after a frost to look like a red raisin (NC State). The fruit has a strong, unpleasant smell (Nutrients review, 2020), and Robin Harford says it smells of musty old socks when cooked. The European guelder rose and the native American highbush cranberry look almost alike. They are told apart by the glands at the top of the leaf stalk: on the European plant they are bowl- or cup-shaped with a distinct rim (NC State), concave and ear-shaped (Ask Extension); on the native plant they bulge outward, club-shaped or columnar (NC State), like matchstick heads (Ask Extension). USDA notes that the two varieties vary into each other. The European fruit is bitter and less desirable for jellies and sauces (NC State; USDA); the native fruit is very tart (Sam Thayer), and USDA says the processed fruit is very similar to cranberry and red currant.

Safety

Eat the fruit cooked, not raw. A peer-reviewed study says raw guelder-rose fruits taste astringent, bitter and sour and are considered slightly toxic because they contain saponin glycosides and viburnine (Protoplasma, 2018). Eat The Weeds says European cranberrybush berries are toxic raw and must be cooked, and Robin Harford calls the raw berries mildly toxic if eaten in too great a quantity. Plants For A Future, a plant database, says large quantities of the fruit can cause vomiting and diarrhea, and that it causes mild upsets when eaten unripe; no safety source checked confirms this. NC State’s pages disagree: its European cranberrybush page says the drupes can be eaten off the bush, while its American cranberrybush page says the European fruit is not edible. Even for the native American variety, an expert answering for Ask Extension says the ripe berries are edible in small quantities. Each fruit has one large, flat seed that is somewhat bitter if chewed (Sam Thayer); strain out seeds and skins after cooking (University of Alaska Fairbanks; Robin Harford). Privets, which the Lady Bird Johnson Wildflower Center and Plant Invaders of Mid-Atlantic Natural Areas pair with viburnums, have berries that NC State lists as poisonous (rarely fatal for Japanese privet), but the berries are black to blue-black (Plant Invaders of Mid-Atlantic Natural Areas), so they do not look like the bright red cranberrybush fruit. No toxic lookalike with red fruit is named in the sources checked. Mapleleaf viburnum, which Virginia Tech lists as a lookalike, also has three-lobed, maple-like leaves, but its fruit ripens bluish-black (NC State); arrowwood, another lookalike Virginia Tech names, has ovate to heart-shaped, coarsely toothed leaves and blue-black fruit (NC State); and unripe pink nannyberries have simple oval leaves and ripen blue-black (Practical Self Reliance; NC State).

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 with red fruit is named in the sources checked; privets, a deadly lookalike of viburnums, have black to blue-black berries (Plant Invaders of Mid-Atlantic Natural Areas). Mapleleaf viburnum also has three-lobed, maple-like leaves but bluish-black fruit (NC State; Virginia Tech pairs them); arrowwood has ovate to heart-shaped, coarsely toothed leaves and blue-black fruit (NC State); unripe pink nannyberries have simple oval leaves (Practical Self Reliance). Cranberrybush fruit ripens bright red.
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 Aug
Peak
early Sep–late Sep
Ends
early Nov

USDA says the fruit is commonly gathered from wild stands in late August or early September, best when picked slightly under-ripe and sour; after a heavy frost it is softer but develops a musty smell when cooked. A review in Nutrients says the fruit can be harvested from late summer to mid-autumn, and by winter it shrivels like dried red raisins; NC State says it shrivels after a frost and hangs on into winter. In Wisconsin, Sam Thayer finds the native fruit can be picked until early November, though it tastes best soon after it ripens. No DC-area source gives dates; the few DC sightings marked as fruiting are from August, September and November.

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 source gives a ripening date. USDA’s national plant guide and Virginia Tech’s fact sheet put ripe fruit in late summer, and DC sightings show fruit in August, so the start is set at late August.

Peak

estimated: No source names a peak for the DC area; September is the month sources from several regions give for ripening and best picking, before frost softens the fruit.

End

estimated: Sources say the fruit can be picked into mid-autumn and early November and then shrivels after frost while hanging on into winter; early November is kept as a cautious end for fruit still worth picking, with the shriveling noted.

Evidence

start: USDA plant guide: 'The fruit is commonly gathered from wild stands in late August or early September'. Virginia Tech (European variety): 'ripening in late summer and persisting through the winter'. iNaturalist: 2 research-grade fruiting-annotated sightings within 25 km of DC in August. | peak: USDA: 'The fruit is commonly gathered from wild stands in late August or early September', best picked slightly under-ripe and sour. NC State (American variety): 'Matures Aug.-Sept.' Protoplasma 2018 (Poland): drupes 'ripening in August (V. lantana) or September (V. opulus)'. | end: Nutrients review (2020): 'They can be harvested from late summer to mid-autumn, and by winter the fruits shrivel and look like dried red raisins.' NC State: 'shrivels after a frost looking like a red raison and persists into winter'. Sam Thayer (Wisconsin): 'the fruit can always be harvested until early November'.

Where to look

Frequently planted and sometimes escaped into thickets, hedgerows and old fields (USDA; Virginia plant atlas). It is logged most in Rock Creek Park, Cabin John Regional Park and Sligo Creek Stream Valley Park, where picking is not allowed. The C&O Canal allows edible fruits generally but sets no limit for cranberrybush (ambiguous: ask the park), and Virginia state parks allow picking but have no logged plants, so pick from planted shrubs on private land with the owner’s permission.

Habitats
old fields & meadows, 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

  • Buddy Attick Lake Park (City of Greenbelt)

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

    Picking rules not checked.

No picking here (4 places)
  • Rock Creek Park

    7 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.

  • Cabin John Regional Park

    4 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.

  • Sligo Creek Stream Valley Park

    4 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.

  • Rock Creek Regional Park (MD)

    3 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.

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

  • jelly: simmer the fruit with chopped oranges and crab apples for 15 minutes, strain it overnight through a jelly bag, then boil the juice with sugar to the setting point (Robin Harford)
  • sauces, jellies and juices (USDA; NC State)
  • jelly, preserves, sauces and wine, used like cranberries (Eat The Weeds)
  • jelly, jams and syrups for pancakes, meat and game (Eat The Weeds)
  • marmalades, jams, cordials, liqueurs and pies in Russian and Ukrainian cooking (Nutrients review, 2020)
  • harvest in late August or early September, slightly under-ripe and sour; after a heavy frost the fruit is softer but smells musty when cooked (USDA)

Keeping

Cook within a few days of picking or freeze the berries; strain out the seeds and skins and freeze the purée, since no tested canning recipe exists for this species.

Use within
within a few days
Keeps fresh
University of Alaska Fairbanks says fresh highbush cranberries (writing about the related Alaska species) keep three to four days covered in the refrigerator, in shallow containers so they are not crushed. Cook before eating.
Canning
no tested recipe: refrigerate or freeze, don’t can
Keeping basis
general guidance for its type

Ways to keep it

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

    Spread firm, sorted berries on a cookie sheet, freeze, then move them to freezer bags or containers; frozen berries last up to two years (University of Alaska Fairbanks, for the Alaska highbush cranberry). Cook before eating.

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

    Crush the berries with a little water, simmer 10 minutes, force them through a sieve or food mill to remove seeds and skins, and freeze the purée; University of Alaska Fairbanks says canning is not a safe way to keep the purée.

  • Jam/jelly as researched: jam/jelly; canning: no tested recipe — refrigerate or freeze

    Robin Harford’s jelly: simmer with oranges and crab apples, strain overnight, boil the juice with sugar. No tested canning recipe exists for European or American cranberrybush, so refrigerate or freeze the jelly.

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

The native variety hybridizes with escaped European plants, which may gradually degrade the native form (USDA; NC State), and NC State says the European plant is sometimes sold as the native in nurseries. Near DC, wild plants are escaped European plants; the native variety is not native to Maryland, Virginia or DC (USDA).

Origin
mixed
Native range
Europe, Asia and North Africa (var. opulus); northern North America, in the US from Maine to Pennsylvania and West Virginia and west to Washington (var. americanum)
Invader credit
☆
Virginia invasive rank
not listed
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
Patchy Estimate 126 = 85 research-grade iNaturalist sightings within 25 km + 58 needs-ID sightings counted at 1.4% (85 of the 6,242 research-grade Viburnum sightings here are European cranberrybush) + 40 'cultivated' (planted) sightings (rule A); that is tier 3 by count (rule B). Rule D does not apply: the Virginia plant atlas says the European variety has "Escaped from cultivation in scattered localities", which says where it grows wild, not that it is rare, and no source calls it rare or very infrequent in Maryland, Virginia or DC. Final tier 3.
Effort
Quick kitchen prep Simmer the berries in a little water for about 10 minutes and press them through a sieve or food mill to remove the seeds and skins, for sauce or purée (University of Alaska Fairbanks); jelly, strained overnight and boiled again with sugar, is a 3.
Find: what this means

1 Everywhere · 2 Common in the right habitat · 3 Patchy · 4 Elusive. This is about how much there is, not whether you may pick it. It is based on iNaturalist sightings within 25 km (about 15 miles) of downtown DC, counted on October 3, 2026. The four rules that each plant’s “Find” reason refers to: (A) the estimate is the confirmed sightings, plus the unconfirmed ones (scaled down where the plant has lookalikes in its genus), plus the sightings marked as planted; (B) the tier by estimate: 1,500 or more is tier 1, 250–1,499 tier 2, 50–249 tier 3, under 50 tier 4; (C) tier 1, Everywhere, also needs a source saying the plant is common in lawns, sidewalks, yards or gardens, vacant lots or towns, or at least one DC street tree of it per km of sidewalk, otherwise it is tier 2; (D) if a reliable source says the plant is rare in this region, or that wild plants rarely bear the harvest, only planted sightings count. iNaturalist is a website and phone app where people post photos of the plants and animals they see. A sighting is “research grade” when other users have confirmed what it is; “needs ID” sightings are not confirmed yet, and “cultivated” ones are marked as planted.

Effort: what this means

1 Grab & eat · 2 Quick kitchen prep (under about 30 minutes) · 3 Real work (hours, or cooking needed for safety) · 4 Project (days or equipment). Scored on the simplest worthwhile use; each plant’s page says why.

Sources

42 sources, each linked to the original.

  1. Prince William Forest Park Superintendent’s Compendium National Park Service, Prince William Forest ParkBacks up: picking rules
  2. C&O Canal NHP Superintendent’s Compendium National Park ServiceBacks up: picking rules
  3. Rock Creek Park Superintendent’s Compendium National Park ServiceBacks up: picking rules
  4. 4VAC5-30-50. Flowers, plants, minerals, etc. Virginia Law Library (law.lis.virginia.gov)Backs up: picking rules
  5. Non-Native Invasive Terrestrial Plant Species in the State of Maryland Maryland Invasive Species CouncilBacks up: picking rules, native or invasive status
  6. Identify a plant (#873238) Ask ExtensionBacks up: description
  7. Viburnum opulus (Cranberry Bush Viburnum, European Cranberry, Guelder-Rose) NC State Extension Gardener Plant ToolboxBacks up: description, habitat, season, safety, uses, picking rules, native or invasive status
  8. Highbush-cranberry, Viburnum opulus L. var. americanum Ait. (Plant Guide) USDA NRCS National Plant Data CenterBacks up: description, habitat, season, uses, safety, picking rules, native or invasive status
  9. Guelder rose: a wild super fruit that smells like old socks (Robin Harford) Eatweeds (Robin Harford)Backs up: description, safety
  10. highbush-cranberry, Viburnum opulus var. americanum (Dendrology fact sheet) Virginia Tech Department of Forest Resources and Environmental ConservationBacks up: description, safety, safety details
  11. Viburnum trilobum (Cranberry Viburnum) NC State Extension Gardener Plant ToolboxBacks up: description, season, safety, uses, picking rules, native or invasive status
  12. European cranberrybush viburnum, Viburnum opulus var. opulus (Dendrology fact sheet) Virginia Tech Department of Forest Resources and Environmental ConservationBacks up: description, season, safety, safety details
  13. Viburnum opulus L.: A Review of Phytochemistry and Biological Effects (Kajszczak et al., Nutrients 2020) Nutrients (MDPI; peer-reviewed), via PubMed CentralBacks up: description, uses, season
  14. iNaturalist research-grade observations of Viburnum opulus within 25 km of downtown DC iNaturalistBacks up: findability
  15. Viburnum opulus var. americanum (American Cranberry Bush) Lady Bird Johnson Wildflower CenterBacks up: habitat
  16. Annotated Checklist of the Vascular Plants of the Washington-Baltimore Area, Part I (Shetler & Orli, 2000) Smithsonian Institution, National Museum of Natural History, Department of BotanyBacks up: habitat
  17. Viburnum opulus L. var. opulus (Digital Atlas of the Virginia Flora) Virginia Botanical Associates (Digital Atlas of the Virginia Flora)Backs up: habitat, picking rules, findability
  18. USDA PLANTS Database: Viburnum opulus (VIOP), native status USDA NRCSBacks up: native or invasive status
  19. USDA PLANTS Database: Viburnum opulus var. americanum (VIOPA2), native status USDA NRCSBacks up: native or invasive status
  20. USDA PLANTS Database: Viburnum opulus var. opulus (VIOPO), native status USDA NRCSBacks up: native or invasive status
  21. Virginia Invasive Plant Species List (effective date: September 2024) Virginia Department of Conservation and Recreation, Division of Natural HeritageBacks up: native or invasive status
  22. 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
  23. Invasive Plants in the District DC Department of Energy & EnvironmentBacks up: native or invasive status
  24. What are these red berries and are they edible? (#845746) Ask ExtensionBacks up: safety
  25. Viburnum opulus, Guelder Rose (Known Hazards) Plants For A FutureBacks up: safety
  26. Differences in the fruit structure and the location and content of bioactive substances in Viburnum opulus and Viburnum lantana fruits (Konarska & Domaciuk, Protoplasma 2018) Protoplasma (Springer; peer-reviewed), via PubMed CentralBacks up: safety, season
  27. Highbush Cranberry: A Loser in the Name Game (Sam Thayer, The Forager, 2001) Thomas J. Elpel’s Wildflowers & WeedsBacks up: safety, season
  28. Highbush Cranberries (FNH-00112) University of Alaska Fairbanks Cooperative Extension ServiceBacks up: safety, storage, keeping
  29. Plant Invaders of Mid-Atlantic Natural Areas, Field Guide (Swearingen & Fulton, 2022), Privet Mid-Atlantic Invasive Plant Council / Passiflora Press (hosted by Bugwood/Mid-Atlantic Invaders Tool)Backs up: safety, native or invasive status, safety details
  30. Viburnum acerifolium (Mapleleaf Viburnum) NC State Extension Gardener Plant ToolboxBacks up: safety, safety details
  31. Viburnum dentatum (Arrowwood) NC State Extension Gardener Plant ToolboxBacks up: safety, safety details
  32. Viburnum lentago (Nannyberry) NC State Extension Gardener Plant ToolboxBacks up: safety, safety details
  33. Nannyberry (Viburnum lentago) (Ashley Adamant) Practical Self RelianceBacks up: safety, safety details
  34. Identification of native blackhaw or non-native ligustrum in Austin (Ask Mr. Smarty Plants, expert answer) Lady Bird Johnson Wildflower CenterBacks up: safety, safety details
  35. Ligustrum japonicum (Japanese Privet, Privet, Wax-leaf Privet) NC State Extension Gardener Plant ToolboxBacks up: safety, safety details
  36. Ligustrum sinense (Chinese Privet) NC State Extension Gardener Plant ToolboxBacks up: safety, safety details
  37. Ligustrum vulgare (Common Privet) NC State Extension Gardener Plant ToolboxBacks up: safety, safety details
  38. Ligustrum lucidum (Glossy Privet) NC State Extension Gardener Plant ToolboxBacks up: safety, safety details
  39. iNaturalist research-grade observations of Viburnum opulus within 25 km of Washington, DC, by month (fruiting annotation) iNaturalistBacks up: season
  40. High-bush Cranberry (Green Deane) Eat The WeedsBacks up: uses
  41. Valuable Viburnums (Green Deane) Eat The WeedsBacks up: uses, safety
  42. Guelder rose jelly (Robin Harford) Eatweeds (Robin Harford)Backs up: uses, safety, keeping