Once found in every medicine cabinet, wintergreen is also an attractive garden plant, with a variety of uses, both decorative and practical. Preparing a description for it, I thought some further background information would be of interest and value, so here goes.
The First Wintergreens
The term ‘wintergreen’ originally simply meant a plant that stayed green during winter – what today we would call an evergreen. In the past, when life was tougher and lived closer to nature, green foliage in winter had both practical and psychological value. During the cold, dark days of winter it was a reminder that life continued, and that in time the sun, warmth and green plants would return again. We still see this in the use of holly and mistletoe at Christmas, and indeed in the Christmas tree itself, which is always an evergreen.
Practically speaking, green leaves in winter had potential value too. Arborvitae (Thuja occidentalis), contains high levels of vitamin C, and was used by native Americans to prevent, and cure, scurvy. It saved the life of Jacques Cartier, the early French explorer and founder, among other things, of Montreal, Canada. Most evergreen plants are not edible – they need strong defenses since they will be so tempting to hungry deer and other small mammals – so they weren’t eaten or used much, despite their obvious appeal.
Meet the American Wintergreen
One big exception, and the plant that we mean today by ‘wintergreen’, are different species in the genus Gaultheria, most importantly the American wintergreen, Gaultheria procumbens. When crushed, this plant has a minty smell, but it isn’t related at all to mint. While the major chemical giving mint its particular characteristics is menthol (and eucalyptol), in wintergreen the active ingredient is methyl salicylate, a volatile form of salicylic acid. That might sound familiar, because it is the active ingredient in aspirin, one of the most commonly-used medicines derived from plants. In both mints and wintergreen, many other compounds are present in smaller amounts, giving the unique characteristics of the many different varieties of mints, for example.
You only have to chew a leaf or berry of wintergreen to release that tangy, minty flavor. That’s exactly what native Americans did with it, for the way, like menthol, it opens the air passages and makes breathing easier. Settlers soon began to do the same, and also made tea from the leaves. By the way, if you want to make the best tea from your wintergreen, the leaves need to be fermented briefly first. This is easy. They are mixed with some water and left in a jug in a warm place, until bubbles appear in the water. Then they can be drained, keeping the water to dilute and use, and then dried. A fruit/vegetable drier is best, rather than the heat of an oven. The dried leaves can then be stored and used as needed.
So popular was wintergreen tea with the French explorers and settlers, it became known as Thé du Canada. During the War of Independence, which you will recall involved throwing tea into harbors, it became a popular drink in America too, as did bergamot (Monarda), which also has a minty flavor. The plant still has the alternative name of ‘teaberry’, and the berries do make an especially good tea, containing vitamin C as well.
It didn’t take long to discover how to extract the actual oil from the leaves. This is done with steam distillation – boiling the water and then letting the oil condense in a still – maybe the same one that was used for moonshine.
Wintergreen oil, when rubbed on the skin, causes a warm, tingly sensation, and was used for aching muscles and general pains – something much more common when physical labor was also more normal, on the farm on in a factory. Being related to aspirin, presumably some is absorbed, acting like a local pain-killer.
A warning – oil of wintergreen is toxic, and shouldn’t be used in tea or eaten in any way. As little as a teaspoon can kill an adult, and much less will kill a child. Don’t use the oil on your skin if you have cuts, or on a child under 2 years old. Some people do find it irritates their skin, and pregnant or breast-feeding women should probably avoid it too. Some people are allergic to aspirin, and because if the chemical similarity they should definitely avoid oil of wintergreen, or suffer serious allergic reactions.
Pleasant, stimulating and temporarily pain-relieving it is, but there is no reliable evidence that oil of wintergreen actually works effectively as a treatment for rheumatoid arthritis, gout, stomach pains, dysmenorrhea, kidney stones, asthma, or stomach pains, despite the claims made.
Wintergreen Oil Today
It seems that most, if not all, of the wintergreen oil available doesn’t come from American wintergreen, but from another species, Gaultheria fragrantissima. This is a sub-tropical species, found in India chiefly, but also in southern China and down through Thailand and Malaysia.
While American wintergreen is a very low-growing plant, this species is a larger evergreen shrub, usually around 3 feet tall, but found in the wild up to 10 or12 feet tall. It seems to be variable, depending on where it is growing across its large range. With attractive white, presumably fragrant flowers, and big crops of purple berries, it’s easy to see why it makes economic sense to use it as source, since the active ingredient is the same. India is by far the largest exporter of oil of wintergreen. Although not apparently being grown in American nurseries, Indian wintergreen is hardy in zone 9, and should grow well in Florida. Like American wintergreen, it needs acidic soil.
A Clean Mouth Too
In a completely different direction, wintergreen oil has another use, probably one that few people realize. Mouthwash is a daily ritual for many people, but it wasn’t always that way. Or at least, not in it’s modern form. Hard to believe, but the ancient Romans imported casks of human urine from Portugal, and used it as mouthwash. In fact, it was still being used in the 18th century, because the ammonia was known to kill germs. Improvements came slowly. An English Doctor called Joseph Lister was the first person, in 1865, to attempt to sterilize a room for surgery, but others soon followed. Two American doctors, Robert Wood Johnson and Joseph Lawrence, became interested in sterilizing. Johnson went on to found, with his brothers, the Johnson & Johnson company, while Joseph Lawrence devised the first liquid antiseptic in 1879. He named it Listerine, in honor of Joseph Lister. In 1895 Lawrence sold the formula to Lambert Pharmaceutical Co. It was first marketed for cleaning wounds, but by 1914 it had become the first mouthwash to be sold (on prescription) in drug stores. The fun part is that a key ingredient, besides alcohol, is oil of wintergreen, which gives it the minty flavor. Of course, it’s the alcohol that makes it effective at killing germs.
Other uses for oil of wintergreen include some chewing gums, some root beers, and some candies too.
Wintergreen in the Garden
American wintergreen is an attractive and easily-grown plant, hardy across most of the country. See the picture at the top of this blog. It does need acidic soil, with a pH below 6.0, but otherwise it makes an easy and effective ground cover for semi-shady areas, with handsome glossy foliage and bright red berries in late fall and early winter. It’s a great example of the intersection of plants, humans and society, and just how useful plants can be – as well as beautiful.