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A Forager’s Year

Field safety

For every outing, whatever you are picking.

Field hazards

Poison ivy (Toxicodendron radicans)

Severity
moderate
Months
all year

Poison ivy is native and common across the DC area. Every part of it carries urushiol, an oil that causes an itchy, blistering rash in most adults: leaves, stems, roots, and even dead plants. Each leaf is made of three leaflets with smooth, wavy, lobed or toothed edges. Leaves are reddish and shiny in spring, green in summer, and yellow, orange or red in fall. Older vines climb trees on dark, hairy aerial rootlets, and the plant also grows as an upright shrub or ground cover. UMD Extension notes that it often grows in among shrubs and ground covers, where it is hard to see. So in mixed berry, grape and honeysuckle tangles along woods edges, assume it is there until you have checked. Virginia creeper (five leaflets) and boxelder seedlings (three leaflets) look similar. This is a year-round hazard. FDA says these plants are dangerous in every season, UMD says dead plants can still cause reactions for a couple of years, and the oil lasts on tools, gloves and clothing for months or longer. Bare winter vines, and digging roots in late fall and winter, still expose you. The oil starts soaking into skin within minutes. A rash usually appears 12 to 48 hours later, though FDA gives a range of a few hours to several days, and it clears in about 2 to 3 weeks without treatment. Never burn it, because the smoke can badly injure the lungs. Poison sumac is covered in the sumac-berries entry and is not repeated here.

Phototoxic plants: wild parsnip and giant hogweed (cow parsnip a lesser risk)

Severity
serious
Months
May, Jun, Jul, Aug

Some members of the carrot family have sap containing furanocoumarins. When sap on the skin is exposed to sunlight, it causes a chemical burn called phytophotodermatitis. NY DEC says wild parsnip (Pastinaca sativa) burns develop within 24 to 48 hours, blister painfully, and can leave discoloration and sun sensitivity that may last for years. Giant hogweed (Heracleum mantegazzianum) is worse. UMD Extension says its sap causes severe burning and blistering and can cause temporary or permanent blindness if it gets in the eyes. Native cow parsnip (Heracleum maximum) is less toxic than giant hogweed, but NY DEC says it can still cause burns that take weeks or months to heal and may scar. PRESENCE: Giant hogweed is rare here. UMD Extension (updated 2026) lists it in only a few Maryland counties since 2003 (Baltimore, Harford, Garrett) and calls it uncommon. A 2003 Maryland Department of Agriculture release said it had been found in DC at that time. Virginia Cooperative Extension says Virginia’s populations (first confirmed in 2018 in Clarke County, then Fauquier and Rockingham, with probable sites in Montgomery County VA and the City of Alexandria) were all planted, did not spread on their own, and have had eradication work. VA DCR lists it as an early-detection invasive, and VDACS regulates it as a Tier 1 noxious weed. Wild parsnip is established but scattered. It is not on Virginia DCR’s 2024 invasive plant list, and no MD or VA agency fact sheet on it was found. GBIF occurrence data show about 150 Maryland records and about 130 Virginia records, mostly from western counties, with a few from Montgomery, Prince George’s and Howard (MD), Fairfax, Arlington and Loudoun (VA), and 4 from DC. It grows along roadsides, ditches and field edges. That is the same open, sunny ground where people dig wild carrot and burdock, which are covered elsewhere.

Ticks: Lyme disease and other tick-borne illness

Severity
serious
Months
Apr, May, Jun, Jul

Lyme disease is the most commonly reported tick-borne disease in Maryland (more than 2,000 cases in 2022, per MDH), in Virginia (over 1,000 reported cases a year for a decade, per VDH), and in DC. It is spread mainly by the poppy-seed-sized nymphs of the blacklegged (deer) tick. CDC says nymphs are out looking for hosts from April through July. VDH puts nymph activity in late spring and early summer, with adults active in fall, on warm winter days and in early spring. DC Health’s 2014-2020 data show local tick-borne illness peaking in June and July, with most cases from May to August. The area has other tick-borne illnesses too: babesiosis, anaplasmosis and ehrlichiosis (DC Health; MDH), and Rocky Mountain spotted fever. The aggressive lone star tick is common in Virginia’s Piedmont and coastal areas. It spreads ehrlichiosis and can cause alpha-gal syndrome, a potentially serious allergy to red meat. Ticks live on grassy, brushy and leaf-littered ground, exactly where people forage, and CDC says exposure can happen in any month. CDC says a tick usually has to be attached for more than 24 hours to pass on Lyme, so daily checks work.

Chiggers

Severity
minor
Months
Jun, Jul, Aug

Chiggers are the tiny larvae of mites (roughly 1/150 inch). They gather where two kinds of vegetation meet: forest-grass borders, brush thickets, swamp edges and overgrown, humid grass. In other words, the edges where berries and greens grow. They attach where clothing is tight (ankles, waistband, armpits, under bra straps). They do not burrow into the skin. UMD Extension says itching usually starts 3 to 6 hours after they attach and can last up to 2 weeks. UMD says eggs are laid in the first warm spring weather. Ohio State puts peak activity in June through August, once temperatures are above about 60 F. No DC-specific season data was found, so treat summer as the peak and late spring and early fall as possible.

Yellowjackets and wasps at fallen fruit and ground nests

Severity
moderate
Months
Aug, Sep, Oct

Yellowjacket colonies reach their largest size from late summer into early autumn. UMass says peak numbers come around Labor Day, and Virginia Cooperative Extension says late summer until early autumn. At that point workers switch from hunting insects to looking for sugar, including ripe, overripe and fallen fruit. That is the same time and place as pawpaw, persimmon, wild grape, late mulberry and apple gathering under trees. Many yellowjackets (Vespula) nest in the ground, often in old rodent burrows, with more than one entrance hole, so a nest can be right under the fruit you are picking up. A yellowjacket can sting repeatedly. When attacking it releases an alarm pheromone that brings out its nestmates, and vibration near a nest can set them off. UMD Extension notes they are especially quick to defend in autumn, when nectar is scarce. People allergic to venom may need medical help after repeated stings.

Thorny invasive thickets (multiflora rose, wineberry, Japanese barberry)

Severity
minor
Months
Jun, Jul, Aug

The best wineberry, blackberry and mulberry spots are often inside thickets of thorny invasive shrubs. UMD Extension describes multiflora rose as having sharp, curved, often paired thorns that form prickly thickets, and wineberry canes as covered in red hairs and prickly spines forming dense thickets. Virginia DCR’s 2024 list rates multiflora rose and wineberry High and Japanese barberry Medium for invasiveness in all three regions of the state. Barberry has a second hazard. The Connecticut Agricultural Experiment Station reports that forests infested with barberry have higher numbers of blacklegged ticks. CAVEAT: No source was found that documents eye injuries to foragers or berry pickers from these plants. The eye-protection advice below comes from Connecticut Agricultural Experiment Station safety guidance for people working on invasive plants with hand tools (gloves and eye protection) and brush saws (long sleeves, safety glasses). It is applied here by analogy to pushing through thorny canes at face height.

Potomac shoreline, high water and summer heat (C&O Canal, Great Falls)

Severity
serious
Months
Jun, Jul, Aug

Many good foraging spots are along the Potomac floodplain and the C&O Canal towpath. The NPS says the river looks calm on the surface but has hidden currents and whirlpools that can pull people under or trap them beneath rock ledges. In the Potomac Gorge at Great Falls, 51% of river-related injuries are fatal, and 72% of incidents involve swimmers, waders, or people who slipped off rocks. At Great Falls Park (VA) it is illegal even to put your feet in the water. The towpath floods regularly when the river overflows, and tributaries can flash-flood. The NPS warns that water over the path may be deeper than it looks and that users can be stranded as it rises. NPS also warns about falling trees and branches along the wooded towpath in high wind, and recommends drinking water before and during summer outings and watching for dizziness or fainting in high heat. Floodplain contamination is covered separately under 'Anacostia and Potomac floodplain contamination'.

Copperheads

Severity
moderate
Months
May, Jun, Jul, Aug, Sep, Oct

The copperhead is the venomous snake foragers are most likely to meet in the DC area. NPS says it is Great Falls Park’s only venomous reptile. Maryland DNR says copperheads cause most of Maryland’s roughly 50 venomous snakebites a year. They rely on camouflage in leaf litter, brush, rock piles and woodpiles, often in sunny canopy gaps. Bites usually happen when someone steps on one, reaches into cover, or tries to handle or kill one. That puts nut gatherers groping in leaf litter, and anyone reaching into brush or under logs, at risk. UVA’s Blue Ridge Poison Center says bites rise in May and June, peak in July, and fall off by late October. Bites cause pain, swelling, bruising and tissue damage. Deaths are rare, but prompt treatment matters.

Deer hunting in local parks during nut season

Severity
moderate
Months
Jan, Feb, Mar, Sep, Oct, Nov, Dec

Fall nut season overlaps with managed deer hunts in suburban parks (where nut gathering itself needs a permit or written permission). Montgomery Parks (MD) runs archery hunting from September through January with the parks open, firearms hunts from October through January that CLOSE the affected parks for 24 hours on scheduled dates, and night-time police sharpshooting from January through March (in 2026–27, January 15 to March 31), when parks and trails are closed from sunset to sunrise. The dates and parks are posted on the Montgomery Parks schedule each season. Fairfax County’s archery program runs every year (in 2026–27, September 12 to February 13) on more than 100 properties. Parks stay open, hunting is Monday through Saturday from 30 minutes before sunrise to 30 minutes after sunset, never on Sunday, from elevated stands at least 50 ft from established trails, and fluorescent orange signs mark the parks where it is authorized. The county reports a strong safety record. The main risk is being off-trail at dawn or dusk in an active archery area, or entering a park that is closed for a firearms hunt.

General safety

Lead and heavy metals in urban soil (DC)

DOEE says leaded gasoline exhaust settled into yards near roads and old exterior lead paint settled into front and back yards, and that some plants can take up lead from soil. UMD Extension says lead builds up in the top 8 inches of soil and does not decline over time. Root vegetables and leafy greens are the main accumulators (carrots take up lead into the edible root), while fruiting crops are lower risk. UMD adds that the bigger concern is eating soil particles stuck to produce, not lead absorbed by the plant. EPA says the greatest risk is soil getting into the mouth or contaminated dust being inhaled, for example from eating unwashed plants. EPA also calls the risk from eating plants grown in contaminated soil minimal, says root vegetables have higher potential to accumulate contaminants, and says fruiting plants (including apple and pear trees and berries) are the most appropriate in potentially contaminated soil. Leafy plants are easily contaminated by dust and soil splashback.

Roadsides, railways and other contaminated edges

EPA lists high-traffic areas (next to heavily trafficked roads, or roads built before leaded fuel was phased out) as sources of lead, zinc and PAHs in soil. Treated lumber can add arsenic, chromium and copper, and petroleum spills at gas stations or tank sites can add PAHs and solvents. University of Missouri Extension advises not harvesting near roadsides or agricultural areas because of vehicle exhaust and pesticide contamination. Federal rules require railroads to control vegetation on and next to the roadbed (49 CFR 213.37). The rule does not specify the method.

Herbicide and pesticide spraying in parks, especially on invasive plants

The edible invasives foragers like are often the very plants that parks treat with herbicide. Montgomery Parks says it uses pesticides to control noxious and invasive pests, including in natural areas, and posts planned applications on its website at least 48 hours ahead. White pre-notification signs go up in advance, and yellow signs at application stay up at least 48 hours. Arlington’s Park and Recreation Commission reported in Nov. 2025 that contractor herbicide treatment is the centerpiece of the county’s invasive-plant program, and that herbicide has been applied to invasives on about two-thirds of the county’s 543 acres of natural land. UMD Extension recommends systemic herbicides (glyphosate, triclopyr) on Japanese knotweed leaves or cut stems, ideally on late-summer regrowth after an early-summer cut. It also says herbicides work on garlic mustard and are most effective in fall and winter. The NPS National Capital Region Invasive Plant Management Team treats invasive plants across the DC-area parks, and the C&O Canal Trust reported 2023 knotweed treatment by 'cut stumping' in C&O Canal NHP.

Anacostia and Potomac floodplain contamination

No authoritative source was found on contamination of plants or produce from Anacostia or Potomac floodplain soils. The DOEE Anacostia River Sediment Project fact sheet names PCBs, PAHs, pesticides, heavy metals and dioxins in river sediment, says the health risk is mainly from eating fish, and says direct contact with the river bottom carries limited risk. It says nothing about plants. Treat this as a reason for caution, not as evidence that floodplain fruit is unsafe.

Positive identification and general foraging safety

University of Missouri Extension’s cardinal rule is to be certain what you are gathering, and to skip a plant when unsure. It suggests learning from experienced foragers and regional guides, washing gathered plants twice, and eating only a small amount of an unfamiliar plant to watch for an allergic reaction. It also says pokeweed contains toxic compounds and should not be eaten. The National Capital Poison Center (poison.org) says to eat wild plants only if you know for certain what they are, and notes that people have died after mistaking poison hemlock for wild carrot.

Poison Control: who to call

Call 1-800-222-1222, the national Poison Help line, or use webPOISONCONTROL online (both free and confidential). The National Capital Poison Center is a DC nonprofit founded in 1980 that long served the metro DC area. It closed its call center on March 31, 2025, for lack of funding. DC-area calls to 1-800-222-1222 now go to neighboring poison centers in Maryland and Virginia. NCPC continues as an automated, all-digital poison control service (webPOISONCONTROL) and still publishes the poison.org plant pages.

Spring floodplain hazard: lesser celandine (fig buttercup, Ficaria verna)

An invasive, low-growing plant with glossy round-to-heart-shaped leaves and shiny yellow 8-petaled flowers that carpets shaded stream floodplains in central Maryland and the DC area from late winter into spring (emerging Feb-Mar, flowering about Mar-May), exactly where and when people gather early greens such as violets, chickweed, garlic mustard and nettles. Its leaves, stems, roots and sap contain protoanemonin, an irritant that causes vomiting, diarrhea and mouth ulcers.

Picking with care

Harvest a small share; leave the plant and plenty for wildlife

Gathering is allowed in NPS parks only where it won’t harm wildlife or a plant’s reproductive potential (36 CFR 2.1(c)(1)). Prince William Forest Park says its gathering limit exists to protect plant reproductive potential, and both PRWI and C&O Canal require that picking not disturb the rest of the plant. Forest Service foraging guidance (Caribou-Targhee NF) recommends staying within suggested amounts so plenty remains for wildlife and regrowth, not trampling or digging more than needed, and correct identification to avoid harming rare plants.

Don’t uproot natives; ramps are at risk

United Plant Savers lists ramps (Allium tricoccum) as at-risk, with an overall at-risk score of 50. Ramps take 7 or more years to set seed, a fully harvested population could take about 150 years to recover, and digging bulbs disturbs the soil and lets invasives in. UpS recommends harvesting leaves only and leaving the bulb, ideally leaving one leaf on the plant. Ramp harvest is illegal in Catoctin Mountain Park because removing the whole plant threatens the population’s long-term viability. In the NPS units around DC, greens and roots cannot legally be gathered anyway; 2.1(c) designations cover only fruits, berries and nuts.

Prioritize invasives (with permission and herbicide caution)

Maryland DNR calls garlic mustard a really aggressive invasive of open woodlands, says the whole plant is edible from root to tip, and publishes a pesto recipe. It recommends harvesting tender new spring growth before the plant flowers. UMD Extension advises pulling garlic mustard before it flowers and sets seed. C&O Canal’s compendium puts no limit on wineberries, an invasive. Two cautions: on most public land, even pulling invasives requires permission (see Where you may pick), and invasive stands are the ones most likely to have been sprayed.