No. 171
Common evening primrose
Oenothera biennis (also O. parviflora)
king’s cure-all; also small-flowered evening primrose
Roots, bulbs & tubers first-year taproot (dug from the rosette, cooked)
Drawing: Britton & Brown, Illustrated Flora (1913)
- Find
- Common in the right habitat
- Effort
- Quick kitchen prep
- ID risk
- Beginner
- Origin
- native
- Uses
- Cooked vegetable / soup
Season
- Jan
- Feb
- Mar
- Apr
- May
- Jun
- Jul
- Aug
- Sep
- Oct
- Nov
- 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.
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 taproot of common evening primrose in its first year, while the plant is still a flat rosette of leaves and before it sends up a flower stalk (Ohio State). The rosette leaves are lance-shaped, 4 to 8 inches long and shallowly toothed (NC State), with a prominent white or reddish midrib (UMass Extension; Ohio State); in fall they may turn reddish-purple (Northern Woodlands). The root is deep, yellow and fleshy (Ohio State), carrot- or parsnip-like (Northern Woodlands; Edible Wild Food), and typically about 8 inches long and ¾ inch thick at the top (Practical Self Reliance). Edible Wild Food calls it fleshy, sweet and somewhat succulent. Raw it is spicy and irritating; boiled, the spiciness drops to a pleasant bite like horseradish and its sweetness comes through (Northern Woodlands).
Safety
No toxicity is reported for common evening primrose (Ohio State; NC State). The raw root is spicy and irritates the throat (Eat The Weeds; Northern Woodlands), so cook it; Eat The Weeds, a foraging site, says it can bother the throat of some people even when cooked and advises trying it carefully and sparingly at first, and no safety source confirms this. Practical Self Reliance notes that some people boil the root in several changes of water if it is too spicy. The only lookalike the sources name for the young plant is cutleaf evening primrose, a smaller relative whose leaves are wavy or irregularly lobed rather than smooth-edged (Ohio State); no source reports it as poisonous, but none confirms it as food. Dig only rosettes near last year’s dead evening primrose stalks, which mark the patch (Northern Woodlands; Practical Self Reliance), and avoid roadsides and other places that may be sprayed with herbicide.
Lookalikes
Cutleaf evening primrose Oenothera laciniata harmless (may be edible)
Looks similar to common evening primrose while young, but its leaves are wavy or irregularly lobed, while those of common evening primrose have smooth edges (Ohio State). It is a small plant, up to about 2 feet tall, with leaves usually about 2 inches long (Lady Bird Johnson Wildflower Center). No source reports it as poisonous, but none confirms it as food; Eat The Weeds says its edibility is in question.
- Common Evening-primrose (Oenothera biennis), Ohio Perennial and Biennial Weed Guide Ohio State University, College of Food, Agricultural, and Environmental Sciences
- Oenothera laciniata (Cutleaf evening-primrose) Lady Bird Johnson Wildflower Center
- Evening Primrose, Oenothera biennis: Foraging Standby (Green Deane) Eat The Weeds
Safety flags
Eat in moderation
Try it carefully and sparingly at first: Eat The Weeds, a foraging site, says all parts can bother the throat of some people even when cooked. No safety source confirms this; Ohio State lists no toxicity.
- Evening Primrose, Oenothera biennis: Foraging Standby (Green Deane) Eat The Weeds
- Common Evening-primrose (Oenothera biennis), Ohio Perennial and Biennial Weed Guide Ohio State University, College of Food, Agricultural, and Environmental Sciences
Safety marks and flags: what this means
Deadly lookalike / Toxic lookalike: a cited source names a lookalike of that danger, recorded near DC (an iNaturalist sighting within 25 km, a DC street tree, or a Smithsonian listing for DC) and looking like the part you eat. Other lookalikes are still listed, marked “not recorded near DC” or as not looking like the part you eat. Deadly means a source says eating it may be fatal or calls it deadly, or NC State rates it high severity with life-threatening symptoms (sources sometimes disagree; for example Virginia creeper). Each plant’s Lookalikes list says how to tell them apart; “harmless (may be edible)” lookalikes are listed so you know a mix-up isn’t dangerous. Cook first: cooking is needed for safety (for daylilies it is a precaution, not a sourced requirement). Eat in moderation: a source says to limit quantity or frequency (for example oxalates in sorrels and dock, ginkgotoxin, safrole). Spray risk: a source says the plant is commonly treated with herbicide in parks or lawns (invasive control, lawn weeds) or, for ginkgo, sprayed to stop fruiting. Contamination: a source says the plant concentrates pollutants. Each plant’s Safety flags list gives the details and sources.
- ID risk
- Beginner
- Why
- No toxic lookalike is named. Cutleaf evening primrose, the relative Ohio State says looks similar while young, has wavy or irregularly lobed leaves rather than smooth-edged ones (Ohio State); evening primrose rosette leaves have a prominent white or reddish midrib (UMass Extension; Ohio State). Dig only rosettes near last year’s dead evening primrose stalks (Northern Woodlands; Practical Self Reliance).
- Soil risk
- higher
ID risk: what this means
How hard it is to harvest safely. Beginner: no dangerous lookalike, and the edible part is not easily confused with a toxic part. Careful: a toxic lookalike, or toxic parts that end up in the harvest unless removed (for example elderberry stems, unripe ground cherries), or other parts of the plant rated medium-or-higher toxicity, with reliable features to separate them. Expert only: a potentially deadly lookalike that is hard to separate, or (for not-recommended harvests like pokeweed) a plant whose safe preparation can’t be guaranteed. Toxic parts that are obviously separate and thrown away anyway (pits, seeds, skins) don’t raise it; the Toxic parts mark carries that warning.
Soil risk: what this means
Based on the part you eat, following the urban-soil lead guidance on the Field safety page: higher for greens, shoots and roots; moderate for flowers; low for fruit, nuts and sap.
Field safety for every outing (poison ivy, ticks, soil, and more)
When to pick
- Starts
- mid Oct
- Peak
- early Nov–late Nov
- Ends
- late Mar
Dig the root between the plant’s first and second seasons: Northern Woodlands gives the cold months from late fall to mid-spring, whenever the ground is not frozen, and Ohio State says the roots are edible if collected in the first year before the plant blooms. Eat The Weeds says the root is best at the end of the first year, in fall, and too late once the flower stalk rises; Practical Self Reliance says that past early spring of the second year the roots become too tough and spicy. No source gives dates for the DC area, so all three boundaries are estimates. Last year’s dead flower stalks, which stand through winter, mark where to look for rosettes (Northern Woodlands; Practical Self Reliance). Fernald and Kinsey (1958) give the roots' season as late autumn, winter and very early spring.
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 start for the DC area; mid October is the start of the fall dig at the end of the rosette’s first season that Eat The Weeds and Northern Woodlands describe.
Peak
estimated: No source names a best month for the DC area; November is the late fall that Eat The Weeds calls best, after a full season of growth and before any hard freeze.
End
estimated: No source gives an end date for the DC area; late March keeps the early-spring dig that Practical Self Reliance and Northern Woodlands describe in Vermont, moved earlier for DC’s earlier spring, before the second-year flower stalk rises.
Evidence
start: Northern Woodlands (Vermont): 'The best time to gather is between a plant’s first and second season, during the cold months from late fall to mid-spring, as long as the ground is not frozen.' Eat The Weeds: 'roots near end of first year'. Ohio State: 'Young plants grow as rosettes over the first winter.' | peak: Eat The Weeds (Green Deane, replying to a reader): 'the roots is best eaten at the end of the first year, read fall after it has had a large basal rosette collecting sun energy all year. When it sends up a flower stalk it is too late'. Northern Woodlands: 'late fall to mid-spring'. | end: Practical Self Reliance (Vermont): 'Past the early spring in the plant’s second year, the roots become too tough and spicy to be palatable.' Northern Woodlands: 'late fall to mid-spring'. Ohio State: 'Roots are edible if collected during the first year before the plant blooms.' Fernald and Kinsey (1958): 'SEASON OF AVAILABILITY: roots, late autumn, winter and very early spring.'
- Evening Primrose: A Spicy Comfort Food (Benjamin Lord, 2021) Northern Woodlands (Center for Northern Woodlands Education)
- Evening Primrose, Oenothera biennis: Foraging Standby (Green Deane) Eat The Weeds
- Common Evening-primrose (Oenothera biennis), Ohio Perennial and Biennial Weed Guide Ohio State University, College of Food, Agricultural, and Environmental Sciences
- Identifying Evening Primrose (& Ways to Use It) Practical Self Reliance
Where to look
Look for flat first-year rosettes near last year’s dead flower stalks in sunny fields, meadows and disturbed open ground; it is logged most at Dyke Marsh, in Rock Creek Park and along Four Mile Run, all places where digging is not allowed. No listed park allows digging roots, so dig only on private land with the owner’s permission, away from roadsides.
- Habitats
- disturbed ground & waste places, vacant lots, 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.
No picking here (5 places)
- Dyke Marsh Wildlife Preserve
Look but don’t pick: GW Memorial Parkway sites (incl. Great Falls VA, Theodore Roosevelt Island, Dyke Marsh) designate nothing for gathering.
- Rock Creek Park
Look but don’t pick: Rock Creek Park’s compendium bans gathering any fruit, nut, berry, seed or greenery.
- Four Mile Run stream valley (Arlington/Alexandria)
Look but don’t pick: Arlington County park rules (flora shall not be removed or disturbed) and Alexandria’s permit rule both apply.
- Huntley Meadows Park
Look but don’t pick: Fairfax County parks ban removing any plant part without written permission.
- Mount Vernon Trail
Look but don’t pick: GW Memorial Parkway sites (incl. Great Falls VA, Theodore Roosevelt Island, Dyke Marsh) designate nothing for gathering.
Most-logged places: what this means
The places with the most research-grade iNaturalist sightings within 25 km of downtown DC (re-counted in October 2026 over every named place, campuses, condominiums and private grounds included), each marked legal to pick or not. A sighting inside several named places counts once, for the smallest of them, but a sighting inside a National Park Service park never counts for a private, campus or unchecked place. iNaturalist shows where people walk and log plants, not true abundance. Private campuses, condominiums, museums, estates and utility land (Pepco’s power-line land near Sligo Creek) are marked “no” (pick only with the owner’s permission); public university campuses, city parks and other places whose picking rules were not checked (county stormwater land, the U.S. Capitol Grounds, Greenbelt’s North Woods, federal facilities such as the National Zoo) are “unknown”. A place needs at least 2 sightings, so plants with very few sightings have no places. At-risk plants (butternut, nannyberry, American chestnut, ramps, riverbank goldenrod) get places like every other plant; each page says why the plant is at risk and gives any advice its sources give. For some places, mostly Rock Creek Park, the iNaturalist map shows more sightings than the count here, because a map link cannot leave out exactly the sightings credited to another place. iNaturalist is a website and phone app where people post photos of the plants and animals they see. A sighting is “research grade” when other users have confirmed what it is; “needs ID” sightings are not confirmed yet, and “cultivated” ones are marked as planted.
Where you may pick
On National Park Service land around DC (Rock Creek Park and other NPS units) gathering leaves, flowers, roots or other non-fruit plant parts is prohibited, because 36 CFR 2.1(c) lets a park designate only fruits, berries and nuts; Rock Creek’s compendium also bars gathering fruits, nuts, berries, seeds, mushrooms or cut greenery. Get permission before picking in county or regional parks or on private land.
- (no listed park)
No park we checked allows it. Anywhere else, ask whoever owns or runs the land.
Where you may pick: what this means
For each park system: “yes” where its current rules (the park’s compendium or regulation) allow this plant or part, with the limit; “ambiguous” where the wording may or may not cover it, so ask the park; “no” where it is not allowed. Rock Creek Park, the GW Parkway sites (including Great Falls VA and Theodore Roosevelt Island), the National Mall, Montgomery and Prince George’s parks, Maryland state parks, and Fairfax and Arlington parks prohibit picking. Wolf Trap National Park for the Performing Arts allows blackberries and raspberries (one gallon per person per day) and chestnuts (one gallon per person per day). National Park Service rules are reissued every year; other parks change theirs from time to time, so check the park’s current rules. The Where you may pick page has every park’s rules.
Ways to use it
- boiled and eaten like potatoes, a Native American use (USDA)
- boiled, then sliced into salads and sandwiches or shredded into soups, risottos, pasta dishes and potato latkes (Northern Woodlands)
- boiled, fried or baked like carrots or parsnips (Practical Self Reliance)
- harvest tip: peel the root before cooking; Practical Self Reliance found the peel very spicy and the peeled root mild and sweet
- harvest tip: if the root is still too spicy, boil it in several changes of water (Practical Self Reliance)
- harvest from late fall to early spring, finding first-year rosettes near last year’s dead flower stalks (Northern Woodlands; Practical Self Reliance)
Keeping
Keep cold and moist in the fridge for a few weeks, or dig them as needed through winter.
- Use within
- weeks
- Keeps fresh
- Weeks refrigerated in a perforated plastic bag (general guidance for root crops). University of Minnesota: root crops want cold, moist storage; perforated plastic bags in the fridge give this for a moderate time, and root cellars give it longer. The roots can be dug as needed from late fall to mid-spring, whenever the ground is not frozen (Northern Woodlands).
- Keeping basis
- general guidance for its type
Ways to keep it
Store whole as researched: root cellar; canning: n/a (not shelf-canned)
General guidance for root crops (University of Minnesota): root cellars provide cold and moist conditions; give ventilation and protect the roots from rodents.
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
- Origin
- native
- Native range
- eastern and central North America (per NC State)
- 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
- Common in the right habitat Estimate 795 = 343 research-grade iNaturalist sightings within 25 km + 717 needs-ID sightings counted at 57% (343 of the 603 research-grade Oenothera sightings here are common evening primrose and its close relatives in Oenothera subsection Oenothera) + 44 'cultivated' (planted) sightings (rule A); that is tier 2 by count (rule B). Rule D does not apply: the Digital Atlas of the Virginia Flora says small-flowered evening-primrose is "Frequent in the mountains, apparenty rare elsewhere.", but that is 9 of the 343 research-grade sightings here, not the harvest as a whole, and the same atlas says the members of the common evening-primrose complex "are common inhabitants of fields, pastures, roadsides, clearings, and other open, disturbed habitats throughout the state". Final tier 2.
- Effort
- Quick kitchen prep Dig the first-year taproot from beside the rosette, loosening the soil deep enough not to snap the tip, peel it and boil it, changing the water if it is too spicy.
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
24 sources, each linked to the original.
- Rock Creek Park Superintendent’s Compendium National Park ServiceBacks up: picking rules
- 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
- Evening Primrose Edible Wild FoodBacks up: description, habitat
- Oenothera biennis (Common Evening Primrose) NC State Extension Gardener Plant ToolboxBacks up: description, habitat, safety, native or invasive status
- Common Evening-primrose (Oenothera biennis), Ohio Perennial and Biennial Weed Guide Ohio State University, College of Food, Agricultural, and Environmental SciencesBacks up: description, habitat, season, safety, effort & ID risk, safety details
- Evening Primrose: A Spicy Comfort Food (Benjamin Lord, 2021) Northern Woodlands (Center for Northern Woodlands Education)Backs up: description, season, uses, safety, effort & ID risk, keeping, safety details
- Identifying Evening Primrose (& Ways to Use It) Practical Self RelianceBacks up: description, season, uses, safety, effort & ID risk, safety details
- Common evening primrose (Oenothera biennis), Weed Herbarium UMass Extension Landscape, Nursery and Urban Forestry ProgramBacks up: description, effort & ID risk
- Oenothera parviflora L. (Small-flowered Evening-primrose) (Digital Atlas of the Virginia Flora) Virginia Botanical Associates (Digital Atlas of the Virginia Flora)Backs up: findability
- iNaturalist research-grade observations of Oenothera subsection Oenothera (common evening primrose complex) within 25 km of downtown DC iNaturalistBacks up: findability
- Common Evening Primrose (Oenothera biennis) (J. Hilty) Illinois WildflowersBacks up: habitat
- 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
- Oenothera biennis L. (Common Evening-primrose) (Digital Atlas of the Virginia Flora) Virginia Botanical Associates (Digital Atlas of the Virginia Flora)Backs up: habitat, findability
- USDA PLANTS Database: Oenothera biennis (OEBI), native status USDA NRCSBacks up: native or invasive status
- Virginia Invasive Plant Species List (effective date: September 2024) Virginia Department of Conservation and Recreation, Division of Natural HeritageBacks up: native or invasive status
- 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
- 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
- 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
- Invasive Plants in the District DC Department of Energy & EnvironmentBacks up: native or invasive status
- Oenothera laciniata (Cutleaf evening-primrose) Lady Bird Johnson Wildflower CenterBacks up: safety, effort & ID risk, safety details
- iNaturalist research-grade observations of Oenothera subsection Oenothera within 25 km of Washington, DC, by month (all observations) iNaturalistBacks up: season
- Evening Primrose, Oenothera biennis: Foraging Standby (Green Deane) Eat The WeedsBacks up: season, safety
- Harvesting and storing home garden vegetables University of Minnesota ExtensionBacks up: storage, keeping
- Plant Guide: Common Evening-primrose, Oenothera biennis (Immel, 2001) USDA NRCS National Plant Data CenterBacks up: uses, habitat