Genus: Gaultheria procumbens
When you see the word wintergreen, you most likely think of the sweet, spicy taste of Wint-O-green Life Savers or some other breath mint or chewing gum that’s common on grocery store shelves. At one time, the source of their flavor would have been wintergreen or sweet birch (Betula lenta), whose bark and twigs are easier to harvest and yield a volatile oil virtually identical to that of wintergreen. Today, the flavoring in these products—and most of the commercial “wintergreen essential oil” that you can buy—is synthetic, but the wintergreen plant is still highly regarded and used by foragers and herbalists for both food and medicine, and gardeners welcome it to carpet shady landscapes.
Wintergreen (G. procumbens) is native from Newfoundland to Manitoba and south to Georgia. It is hardy from USDA Zone 3 to the cooler parts of Zone 7. Look for the plants in well-drained woodlands and clearings, and in acidic, frequently poor soil in the shade of evergreens such as mountain laurel and rhododendrons.
Wintergreen is a creeper (procumbens means “lying flat”). Inconspicuous stems sprawl on or just below the soil surface. At intervals, erect, mostly naked stems rise 3 to 7 inches above the ground, and a few leathery, oval leaves up to 2 inches long with barely visible rounded teeth are clustered near the top. The leaves are glossy and dark green above, paler and dotted with glands underneath, and they turn red or bronze in the fall. In July and August, white or pink-tinged bell-like flowers about 1/4 inch long hang singly from short stalks in the leaf axils, each “bell” having five small scallops at the open end. The 1/4-inch round scarlet fruits, technically capsules enclosed in a fleshy calyx but popularly known as berries, persist on the plants through the following summer. Thus, it is possible to see a plant bearing this year’s flowers and last year’s fruit at the same time. It’s more typical, though, to see a sparse patch of greenery with neither flowers nor berries.
Wintergreen makes a lovely, low ground cover for a shady garden of native plants. If you are thinking of using it in place of a conventional turf-grass lawn, be aware that it will not tolerate much foot traffic; however, you won’t have to mow it. Success with wintergreen is most likely if your soil is quite acidic (pH as low as 4.5) and high in organic matter. Seeds are available, but germination is slow. Sow seeds in a mixture of sand and peat and keep the flats or pots in a cold frame until the seedlings emerge.
A faster way to start a wintergreen patch is with plants, which are available at many nurseries. Do not dig plants from the wild. Choose a spot with at least part shade in the North or full shade in the South. Set the plants a foot or so apart, and keep them moist. When established, they will slowly spread and fill in the area. Under favorable conditions, the plants will spread indefinitely. Topdress them in the spring with leaf mold or compost.
Medicinal Uses for Wintergreen
Wintergreen’s effectiveness against pain is due to the action of methyl salicylate, which constitutes about 99 percent of wintergreen’s essential oil. This compound is similar to aspirin (acetylsalicylic acid) and, when digested, acts almost exactly like it. A tea made from wintergreen leaves can help ease a fever and take the edge off of a headache. However, any caution that applies to aspirin also applies to wintergreen tea. Because of the danger of Reye syndrome, don’t give wintergreen in any form to children or teenagers who are ill with chickenpox or flu. Pregnant women or those who have ulcers or other stomach problems, or are taking aspirin or anticoagulants should not take wintergreen internally. Others should use wintergreen tea only in moderation and stop drinking it if they experience nausea, vomiting, or ringing in the ears.