Why the verge is tempting, and what it actually holds

There is something irresistible about a hedgerow heavy with elderberries on the walk home, or a roadside hazel you can raid in ten minutes. The trouble is that everything growing on a busy verge is also standing in the fallout of modern traffic. Foraging near roads is not automatically off-limits, but it does demand a clear-eyed understanding of what you are picking through.

Roadside soil and foliage gather a specific cocktail: lead from decades of leaded petrol, much of which is still bound in the top few centimetres of soil; zinc and cadmium from tyre wear and brake dust; polycyclic aromatic hydrocarbons from exhaust fumes and asphalt; road salt spread through winter; and a steady drift of herbicides and pesticides from council cutting regimes and neighbouring farmland.

Heavy metals are the real concern, because they do not wash off. They are drawn up into plant tissue, and they linger in soil for decades after the traffic that produced them has moved on.

Judging a site before you pick

Train your eye to read a verge the way you would read a mushroom habitat. A handful of quick assessments will tell you most of what you need to know.

• Distance from the kerb: as a working rule, avoid anything within 30 metres of a busy A-road, and 50 metres for leafy greens. On a quiet single-track lane the risk drops away quickly, but still favour 10 to 15 metres.
• Traffic volume and type: motorways, lorry routes and roundabout approaches are the worst offenders. HGV traffic throws up far more brake and tyre particulate than a lane used by a dozen cars a day.
• Ditches and drains: runoff concentrates here, so a ditch-side crop is a poor choice even when it looks lush.
• Sprayed land: if the hedge sits on a field boundary, drift from herbicide and pesticide applications is a real consideration, particularly on a windy day or shortly after spraying.
• Railway land: aside from being a trespass offence, railway embankments are routinely treated with herbicide and carry their own hazards. Leave them alone.
• Industrial sites and brownfield land: old gasworks, smelters, scrapyards and demolition sites can hold arsenic, chromium and worse in the soil. A derelict yard is not a larder.

Finding the safer side of the hedge

Once you know what to avoid, the better sites become obvious. Distance is your greatest ally, followed by elevation and orientation. Contaminants settle, so fruit and leaves growing at head height or above on a bank are cleaner than anything trailing near the soil.

In the UK our prevailing wind is south-westerly, so where a road runs roughly north to south, the eastern verge will generally receive less airborne deposition than the western one. It is not a perfect rule, but it is a useful tie-breaker when choosing between two spots.

Better still, look for hedgerows well back from any carriageway: woodland rides, old field boundaries, canal towpaths away from moorings, the edges of quiet lanes, churchyards and allotment boundaries. Always check access first. A public footpath gives you the right to pass along, not to strip the hedge, and picking fruit from private land needs the landowner's permission.

Where risk concentrates, species by species

Not every part of a plant carries the same burden, and understanding this lets you make smarter choices.

• Leaves and flowers are the highest risk. A broad, sticky surface catches and holds airborne particles, and you eat the whole thing. Lime, beech, hawthorn and elderflower picked from a roadside are best left.
• Fruit sits in the middle. The skin holds most of the contamination, so peeling apples, pears and quince makes a real difference. Berries such as blackberries, sloes and rosehips can be washed and cooked, but never pick them from the spray zone of a main road.
• Nuts are the safest of the tree crops, because the shell is genuine packaging. Hazels, sweet chestnuts and walnuts gathered from a quiet lane are a sound bet, provided you crack them out of their shells and discard the shells entirely.
• Sap is filtered by the tree itself as it moves through the xylem, so the liquid is comparatively clean. The weak point is the tap hole and the collecting vessel, both exposed to the air. Avoid tapping roadside trees, use food-grade tubing and containers, and boil the sap before use.

Washing, soaking and trimming: a proper routine

Washing will not remove heavy metals that the plant has already absorbed, which is exactly why site selection matters more than scrubbing. It will, however, shift soil, dust, insect residue and a good deal of surface spray.

• Knock off loose debris at the site rather than carrying it home in your basket.
• Rinse everything in cold running water, changing the water at least twice.
• Soak leafy greens for ten minutes in cold water with a splash of vinegar or a teaspoon of bicarbonate of soda, then rinse again thoroughly.
• Give soft fruit a short soak in one part vinegar to three parts water, then rinse well and drain.
• Trim properly: discard outer leaves, stem bases and any fruit that has touched the soil.
• Peel fruit destined for jams, jellies and chutneys wherever the recipe allows. Cooking does not destroy heavy metals.
• Wash your hands, your knife and your basket before you handle anything else, and never graze as you pick.

Good habits to carry through the year

Rotate your picking spots rather than returning to the same hedge every season, and favour a handful of clean sites over dozens of marginal ones. Keep a few notes on your phone about where you picked and what the traffic was like, so you can make better decisions next autumn.

Finally, be honest with yourself about the edge cases. If a crop looks dusty, smells of diesel, or sits within reach of a lorry's spray, walk on. There is always another hedge, and the whole pleasure of foraging lies in coming home with something you are genuinely glad to cook and eat.