Preview. This site is being tested before the printed calendar is finished, and pages may still change. See the calendar (preview PDF)

A Forager’s Year

No. 46

Blackberry & dewberry

Rubus allegheniensis, Rubus flagellaris and related Rubus spp.

wild blackberries and dewberries

Fruit ripe berries

Drawing: Britton & Brown, Illustrated Flora (1913)

Find
Common in the right habitat
Effort
Grab & eat
ID risk
Beginner
Origin
mixed ☆
Uses
  • Eat raw / salad
  • Baking & desserts
  • Jam & jelly
  • Syrup & cordial

Season

  1. Jan
  2. Feb
  3. Mar
  4. Apr
  5. May
  6. Jun
  7. Jul
  8. Aug
  9. Sep
  10. Oct
  11. Nov
  12. Dec

in season peak

What these mean

Find

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

Effort

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

ID risk

How hard it is to harvest safely. Beginner: no dangerous lookalike, and the edible part is not easily confused with a toxic part. Careful: a toxic lookalike, or toxic parts that end up in the harvest unless removed (for example elderberry stems, unripe ground cherries), or other parts of the plant rated medium-or-higher toxicity, with reliable features to separate them. Expert only: a potentially deadly lookalike that is hard to separate, or (for not-recommended harvests like pokeweed) a plant whose safe preparation can’t be guaranteed. Toxic parts that are obviously separate and thrown away anyway (pits, seeds, skins) don’t raise it; the Toxic parts mark carries that warning.

Native or not, and the invader stars

Origin is where the plant comes from: native, non-native, or mixed (the harvest covers both). The stars rate plants on invasive plant lists: ★★★ Virginia DCR “High” or Maryland prohibited invasive · ★★ Virginia “Medium” · ★ Virginia “Low” · ☆ listed only by the Maryland Invasive Species Council or the Mid-Atlantic Plant Invaders guide (advisory) · no stars: native or not listed.

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

Thorny brambles, mostly native, though introduced Himalayan and cutleaf blackberries (listed as invasive by the Maryland Invasive Species Council) also grow wild here. Allegheny blackberry has stout, angled, reddish-purple canes that stand upright and then arch. Dewberries trail along the ground with stems up to 15 ft long. The thimble-shaped berries go from green to red to glossy black and turn dull black when fully ripe. Unlike raspberries, the core comes away inside the berry. They are sweet-tart and seedy.

Safety

None notable. Aggregate black berries on thorny canes have no dangerous lookalikes. Watch for thorns, and check for ticks after picking in thickets.

Safety flags

Safety marks and flags: what this means

Deadly lookalike / Toxic lookalike: a cited source names a lookalike of that danger. Deadly means a source says eating it may be fatal or calls it deadly, or NC State rates it high severity with life-threatening symptoms (sources sometimes disagree; for example Virginia creeper). Each plant’s Lookalikes list says how to tell them apart; “harmless (may be edible)” lookalikes are listed so you know a mix-up isn’t dangerous. Cook first: cooking is needed for safety (for daylilies it is a precaution, not a sourced requirement). Eat in moderation: a source says to limit quantity or frequency (for example oxalates in sorrels and dock, ginkgotoxin, safrole). Spray risk: a source says the plant is commonly treated with herbicide in parks or lawns (invasive control, lawn weeds) or, for ginkgo, sprayed to stop fruiting. Contamination: a source says the plant concentrates pollutants. Each plant’s Safety flags list gives the details and sources.

ID risk
Beginner
Why
Aggregate black berries on thorny canes have no dangerous lookalikes.
Handling hazards
Thorns (minor)
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.

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
late Jun
Peak
mid Jul–mid Jul
Ends
early Aug

Dewberries ripen first (NC State gives May-July), then the upright Allegheny blackberry, which NC State lists for July. Virginia DWR places both after wineberry, so around DC expect the first ripe berries from late June. A berry is fully ripe when it has lost its shine and turned dull (University of Maryland Extension); red or shiny-black berries are still sour.

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, end

Start

estimated: Virginia DWR says blackberries and dewberries ripen after wineberry, which starts in late June around DC, and DC iNaturalist fruiting records rise from late June. NC State’s May-July dewberry range is from North Carolina; a few early dewberries may ripen a little sooner.

Peak

sourced

End

estimated: No source gives an end date for the DC area; early August allows for late canes and shaded patches after the last DC records.

Evidence

start: NC State: dewberry 'Fruit displays from May to July'. Virginia DWR: blackberries and dewberries ripen after wineberry. DC iNaturalist fruiting records for Allegheny blackberry by third of the month (days 1-10, 11-20, 21-end): June 2/2/6, July 4/9/1; the first records, in early June, are likely green fruit, and the rise comes in late June. | peak: NC State: Allegheny blackberry 'Fruit displays in July.' DC iNaturalist fruiting records peak Jul 9-22 (11 of 24 records). | end: DC iNaturalist fruiting records end in the week of Jul 23-29. NC State: 'Drupes develop later in the summer.'

Where to look

Old fields, roadsides and sunny edges: legal on the C&O Canal towpath, at NACE sites such as Greenbelt Park and Anacostia Park, and at Wolf Trap (one gallon a day; its compendium names blackberries, not dewberries separately), while the logged patches along Four Mile Run and at Huntley Meadows are look-only.

Habitats
old fields & meadows, woods edges, trailsides & thickets
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

  • Greenbelt North Woods and Hamilton Woods

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

    Picking rules not checked.

No picking here (4 places)
  • Huntley Meadows Park

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

    Look but don’t pick: Fairfax County parks ban removing any plant part without written permission.

  • Suitland Bog Natural Area

    5 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.

  • Glencarlyn Park

    5 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.

  • Rock Creek Park

    4 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.

Most-logged places: what this means

The places with the most research-grade iNaturalist sightings within 25 km of downtown DC (re-counted in October 2026 over every named place, campuses, condominiums and private grounds included), each marked legal to pick or not. A sighting inside several named places counts once, for the smallest of them, but a sighting inside a National Park Service park never counts for a private, campus or unchecked place. iNaturalist shows where people walk and log plants, not true abundance. Private campuses, condominiums, museums, estates and utility land (Pepco’s power-line land near Sligo Creek) are marked “no” (pick only with the owner’s permission); public university campuses, city parks and other places whose picking rules were not checked (county stormwater land, the U.S. Capitol Grounds, Greenbelt’s North Woods, federal facilities such as the National Zoo) are “unknown”. A place needs at least 2 sightings, so plants with very few sightings (rugosa rose) have no places. No most-logged places are named for at-risk plants (ramps, chinquapin, American chestnut); chinquapin’s page names Mason Neck State Park, where picking is legal, and asks you to leave most nuts. For some places, mostly Rock Creek Park, the iNaturalist map shows more sightings than the count here, because a map link cannot leave out exactly the sightings credited to another place. iNaturalist is a website and phone app where people post photos of the plants and animals they see. A sighting is “research grade” when other users have confirmed what it is; “needs ID” sightings are not confirmed yet, and “cultivated” ones are marked as planted.

Ways to use it

  • eat fresh
  • pie
  • cobbler
  • jam/jelly
  • syrup
  • freeze

Keeping

Refrigerate unwashed and freeze or make jam within 1-3 days of picking.

Use within
within a few days
Keeps fresh
Refrigerate unwashed; use within 1-3 days (USU), or 2 days (University of Kentucky).
Canning
lab-tested: jam, jelly, whole berries (NCHFP)
Keeping basis
specific to this plant

Ways to keep it

  • Can as researched: can (water bath); canning: lab-tested: whole berries (NCHFP)

    Blackberries and dewberries are on NCHFP’s tested 'Berries - Whole' list.

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

    NCHFP dry pack or tray pack (freeze on a tray, then pack), or a sugar or syrup pack for desserts.

  • Jam/jelly as researched: jam/jelly; canning: lab-tested: jam, jelly (NCHFP)

    NCHFP berry jam, and blackberry jelly with or without added pectin (boiling-water canner).

  • Syrup as researched: syrup/cordial; canning: no tested recipe — refrigerate or freeze

    Freeze or refrigerate homemade syrup. Note that NCHFP’s canned berry-syrup recipe does not list blackberries.

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

Named species (R. allegheniensis, R. flagellaris, R. pensilvanicus) are native, as is topsy blackberry (R. pascuus; iNaturalist lists it as native to Virginia and the United States), 4 of the 161 research-grade sightings within 25 km. Two introduced blackberries occur in the region: Himalayan blackberry (R. armeniacus/R. bifrons, Eurasian) and cutleaf blackberry (R. laciniatus, European); both are on the MISC invasive list but neither is ranked by VA DCR or regulated by MDA.

Origin
mixed
Native range
mixed: native blackberries and dewberries are eastern North American; Himalayan blackberry (R. armeniacus/R. bifrons) is Eurasian and cutleaf blackberry (R. laciniatus) European
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
Common in the right habitat Estimate 297 = 161 research-grade iNaturalist sightings within 25 km + 3,593 needs-ID sightings counted at 3% (161 of the 5,347 research-grade Rubus sightings here are blackberries and dewberries (subgenus Rubus)) + 28 'cultivated' (planted) sightings (rule A); that is tier 2 by count (rule B). Of the 161 research-grade sightings, 60 (37%) are introduced Himalayan (R. armeniacus, 47) and cutleaf (R. laciniatus, 13) blackberries. Final tier 2.
Effort
Grab & eat Pick ripe berries and eat; cobbler, jam and freezing are extra.
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

27 sources, each linked to the original.

  1. C&O Canal NHP Superintendent’s Compendium, effective September 11, 2026 National Park Service, Chesapeake and Ohio Canal NHPBacks up: picking rules
  2. Rock Creek Park Superintendent’s Compendium (2026) National Park Service, Rock Creek ParkBacks up: picking rules
  3. Wolf Trap National Park for the Performing Arts, Compendium of Regulatory Provisions (2026 ver. 6/5/2026) National Park Service, Wolf Trap National Park for the Performing ArtsBacks up: picking rules
  4. Growing Raspberries and Blackberries in the Home Garden University of Maryland ExtensionBacks up: description
  5. Allegheny blackberry (dendrology fact sheet) Virginia Tech DendrologyBacks up: description
  6. Berried Treasure (Xplor, July 2024) Missouri Department of ConservationBacks up: effort & ID risk
  7. iNaturalist research-grade observations of Rubus subgenus Rubus (blackberries and dewberries) within 25 km of downtown DC iNaturalistBacks up: findability
  8. Freezing Blackberries or Dewberries National Center for Home Food Preservation (Univ. of Georgia)Backs up: keeping
  9. How to Preserve Berries Utah State University ExtensionBacks up: keeping
  10. Blackberries (Plate It Up commodity page) University of Kentucky Cooperative Extension, Family and Consumer SciencesBacks up: keeping
  11. Blackberry (FoodLink produce sheet) Purdue Extension FoodLinkBacks up: keeping
  12. Berries-Whole (canning) National Center for Home Food Preservation (Univ. of Georgia)Backs up: keeping
  13. Making Jelly without added Pectin National Center for Home Food Preservation (Univ. of Georgia)Backs up: keeping
  14. USDA PLANTS Database: Rubus allegheniensis (RUAL), native status USDA NRCSBacks up: native or invasive status
  15. USDA PLANTS Database: Rubus flagellaris (RUFL), native status USDA NRCSBacks up: native or invasive status
  16. USDA PLANTS Database: Rubus pensilvanicus (RUPE3), native status USDA NRCSBacks up: native or invasive status
  17. USDA PLANTS Database: Rubus armeniacus (RUAR9), native status USDA NRCSBacks up: native or invasive status
  18. USDA PLANTS Database: Rubus laciniatus (RULA), native status USDA NRCSBacks up: native or invasive status
  19. Virginia Invasive Plant Species List (effective date: September 2024) Virginia Department of Conservation and Recreation, Division of Natural HeritageBacks up: native or invasive status
  20. 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
  21. 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
  22. 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
  23. Invasive Plants in the District DC Department of Energy & EnvironmentBacks up: native or invasive status
  24. Allegheny blackberry research-grade observations within 25 km of DC, by week (fruiting annotation) iNaturalistBacks up: season
  25. Rubus allegheniensis (Allegheny Blackberry) NC State Extension Gardener Plant ToolboxBacks up: season, description, uses, habitat
  26. Rubus flagellaris (Dewberry) NC State Extension Gardener Plant ToolboxBacks up: season, description, uses, habitat
  27. Seeking the Super Six Summer Fruits Virginia Department of Wildlife ResourcesBacks up: season, description, uses, habitat