Q. I’m afraid of mixing up edible plants with toxic ones. Any tips?
A. During the winter and early spring, before plants mature in size and begin to bloom, it is easy to misidentify the green friends and foes. Even well-seasoned gardeners and naturalists can be fooled by the foliage of new growth. In my herb garden, I allow volunteer seedlings from established plants and gifts brought to the garden by birds, moving mammals and the wind. In wild, uncultivated spaces, diversity reigns. While the “innocent-until-proven-guilty” policy can be rewarding, to stay safe one must be certain of the identity of botanicals before ingesting them—some useful herbs have harmful lookalikes.
Four herbs that have similarly shaped wooly leaves are comfrey (Symphytum officinale), Russian comfrey (S. ×uplandicum), wild comfrey (Cynoglossum virginianum) and foxglove (Digitalis purpurea). It is easy to confuse these plants in the early spring. They all have hirsute leaves and like to grow near trees and in humus-rich soil.
All of these plants that share the common name comfrey have been used medicinally in folk traditions. Symphytum poultices and infusions have been used externally to treat bruises and sprains. Home herbalists who choose to drink the tea or swallow any part of the plants should be warned that Symphytum comfrey contains dangerous pyrrolizidine alkaloids that are toxic to the liver. Internal use of these plants is not recommended by the Food and Drug Administration (FDA) or the Federal Trade Commission (FTC) and, since July 2001, products that were meant to be taken internally that contained comfrey and other plants with pyrrolizidine alkaloids have been removed from the market. Nevertheless, some people continue to use comfrey internally.
Wild comfrey (Cynoglossum virginianum) is native to eastern U.S. deciduous forests. Though it is listed on the FDA Poisonous Plant Database, I was unable to find any documentation of human fatalities from eating, drinking an infusion or smoking the leaves of this plant. Wild comfrey is listed in A Field Guide to Medicinal Plants Eastern and Central North America (Houghton Mifflin Company, 2000) by Steven Foster and James Duke as a herb used by Native Americans and by herbalists in the 19th century as a substitute for Symphytum.
People who ingest any of the comfreys should be careful not to mistake them for foxglove (Digitalis purpurea). This beautiful but deadly cottage garden biennial has escaped from cultivation, naturalizing in moist, shady locations in temperate climates. The leaves contain the cardiac glycoside digitoxin. In carefully measured therapeutic doses, Digitalis saves lives as a modern medication against heart failure. According to A Field Guide to Venomous Animals and Poisonous Plants (Houghton Mifflin Company, 1994) by Steven Foster and Roger Caras, mistaking Digitalis for Symphytum has caused accidental fatal poisonings.
Two other common garden plants with somewhat similar leaves, especially in the spring, are garlic (Allium sativum) and daffodils (Narcissus spp.). Both have long, slender and flat leaves that are attached to bulbs below the earth. The best way to tell the difference between toxic Narcissus and the alliums is by using the sense of smell. Daffodils have none of the characteristic sulfur odor of the alliums. Narcissus bulbs and leaves contain the alkaloid lycorine. Fatalities are rare, but the symptoms include bloody diarrhea, vomiting, body tremors and extreme salivation.
Apiaceae is the new name for members of the old Umbelliferae, or umbrella, family, to which a host of useful foods and culinary herbs and a few famously deadly plants belong. While most urban gardeners need not worry about mistaking poison hemlock for a carrot, wild foods enthusiasts need to be very careful to know one from the other.
The mother of all carrots is called Queen Anne’s lace (Daucus carota). It is a biennial, native to temperate Europe and Asia, that has naturalized throughout much of the eastern United States. The leaves are finely cut and resemble carrot foliage; the stems are hairy. The roots are white and can be dug and used just like carrots in the first year of growth. Queen Anne’s lace grows in high and dry places such as meadows, gardens and along roadsides. The roots tend to be small and tough when found growing on the uncultivated land. A shrewd wild foods forager might venture down to lower ground, such as a ditch (where the soil is rich and damp) in search of larger roots. Beware, though—poisonous members of the Apiaceae family often grow in these places.
Poison hemlock (Conium maculatum), like Queen Anne’s lace, is a biennial. The difference between them is that poison hemlock is usually much larger and has hollow, grooved, smooth stems with purple splotches. Be careful not to get the wrong seedling, as a small nibble can cause paralysis and a nasty death.
Be not afraid—rather, be well-informed and cautious when wildcrafting and harvesting unfamiliar plants for food or medicine. Study your field guides, attend hikes and classes led by knowledgeable individuals, and most importantly, do no harm.