Conservation and Safety

Poisonous plants, some of which are deadly, sometimes grow alongside edible plants, so you must identify every plant with 100 percent certainty before you eat it. There is no other foolproof method to determine whether something is edible. Look up all of a plant's identifying characteristics, and make sure they match all your observations. Then, check the accompanying descriptions of any possible look-alikes (especially toxic species), to make sure their key identifying characteristics don’t match.

Cross-check any reference books you use, especially regarding medicinal plants. Other sources may simply repeat folklore from earlier books, without regard for accuracy or safety. When you look up a plant in more than one book, make sure it has the same scientific name, or you may poison yourself with sloppy semantics. Edible and poisonous plants sometimes have the same common name, and names vary from region to region and country to country. Scientific names are universal, and longer-lasting.

Start by learning a few easy-to-identify plants well. There are some people who have accompanied me on my well-attended nature tours in and around New York City who want to learn the whole country's flora in one afternoon. I am forced to announce that learning about too many plants at once causes not only confusion, but permanent brain damage. The malady is called Dementia Botanica, and its first symptom is total destruction of good judgment: victims laugh at my jokes.

Don’t work with plants that have poisonous parts, or become poisonous when they mature, until you have years of experience with safer plants. There are plenty of completely safe species to start off with. Wild foods and instant gratification don’t always mix: you must sometimes follow a plant through an entire year before you know it well enough to eat. Many plants are the easiest to identify in seasons when they’re not edible. If you return to the same location throughout the year, you’ll come to recognize them at their edible stages.

Learn the common poisonous plants in your region, especially those that resemble edible ones. It will make foraging safer, and it will provide a last resort if the in-laws get out of hand.

Get permission to forage on private property. In New York City, I'd occasionally snatch a few handfuls of chickweed from someone's lawn, with no problem. But when I was in New Orleans, and was tempted to examine a plant in an overgrown area on posted property, my local friend told me never, ever to do that there. In some regions, people literally do shoot first, and ask questions later.

Find out if your foraging grounds have been sprayed before you pick. Many parks prohibit spraying, but some of the best plants grow in the partially shaded, disturbed habitats alongside railroad tracks. However, railroads often spray their right-of-way with very dangerous herbicides.

Wash your plants thoroughly under running water before eating them. Any undesirable natural deposits on their surfaces, such as traces of animal droppings, will wash away. (Nobody in their right mind would pick anything with visible animals droppings.)

Never collect rare or legally protected plants. There aren’t usually enough of them to be worth eating anyway, and we want to encourage environmental recovery. Don’t even pick common plants where they’re rare. You’ll collect them more rapidly where they’re common, and they'll probably be of superior quality where they’re thriving. Collect only the parts of the plants you’re going to use. Don’t uproot plants when you’re only going to use the leaves. This is a common error small children make. You can gently explain the correct procedure.

Use common sense to assure that you don’t harm the plants you're collecting. If you trample down bramble bushes to get every last berry, you’re destroying future crops. Leave more than enough mature plants to reproduce and ensure that you have a future supply. Take only what you’re going to use, and collect no more than ten percent of any plant—less if you’re sharing the foraging ground with other people. If you’re collecting roots, be especially careful to collect only a tiny fraction of the most common root vegetables, since you’re destroying them.

Don’t collect near heavy traffic. Lead, the worst pollutant in exhaust fumes, usually settles within fifty feet of the road. Leave a much wider margin just in case. Most gasoline today is unleaded, but the soil may be contaminated from earlier times.

Leaves, roots, and stems contain the most lead. Fruits, berries, and nuts accumulate the least. Some plants, like wild onions, have a greater affinity for accumulating heavy metals than others. Environmental geologists are just beginning to experiment with such plants to remove contamination from soil.

Faster-growing species tend to pick up less heavy metal than more slowly growing ones. As a jazz aficionado, I have no affinity for heavy metal. But if you find a tempting plant growing in a contaminated area, chances are that with some persistence, you’ll also eventually find it in a cleaner location. Most wild foods are called "weeds" because they’re so widespread and prolific. You just may not be spotting them yet.

Collect the right part of the plant in the appropriate season. Be careful not to collect parts of poisonous plants along with your edibles. A foreign family who knew barely any English attended many of my New York City park tours. Once, I pointed out a nonpoisonous, flavorless mushroom, then moved on to lady’s thumb. The family insisted on picking the mushrooms. I don’t know whether they were being stubborn, or they didn’t understand me. Everyone else was standing in the hot sun, waiting for me to discuss lady’s thumb. I blew my whistle, signaled with my arms, and even turned red in the face, but they wouldn't come over to where the rest of the group was. I finally gave up and went over the new species, cautioning everyone about the poisonous dogbane growing alongside.

Suddenly, a few minutes later, while everyone was happily collecting lady’s thumb, I noticed half a dogbane plant, oozing toxic white sap.

Where was the other half? I inspected the family's bag first (they had finally joined us), and sure enough, there it was.

Your local Environmental Protection Agency branch will test you water for pathogenic microorganisms free of charge.

It’s much easier to avoid putting debris into your bag, than sorting out trash later on. Put as little non-edible material in your bags as possible. This saves immeasurable time at home.

Put each species in separate bags. Enclose an index card or label in each bag, with the name of the plant and any notes, especially if you're attending a field walk where the instructor identifies many plants. Seal wild vegetables in plastic bags to keep them from wilting.

If you do bring poisonous plants home for study, be sure they’re clearly labeled. Take further precautions if necessary. Other family members may assume anything in the refrigerator is fair game for snacking, and small children may eat anything they can get into their mouths.

Wash all edibles in luke-cool running water just before you use them, but don’t store them wet, or they’ll spoil more quickly (Microorganisms thrive in damp settings). If you think a wild plant or a wild food dish has gone bad, throw it out. Don’t risk food poisoning.