Scientific Name: Gaultheria procumbens
Family: Ericaceae (the Heath or Heather family)
While most famous for its classic, minty smell, this low-growing, slow-growing eastern North American native shrub is a great, evergreen groundcover for shady spots. It prefers acidic soils, and could be a great partner to blueberries, pines, or other acid-loving plants. It attracts beneficial insects, is drought-tolerant, thrives in the shade, has edible berries and leaves, and has a long history of medicinal uses. Wintergreen is a fantastic, niche-plant for the Forest Garden.
Native to Northeastern North America, but found in most places west of the Mississippi River and south to Georgia in the United States, Wintergreen was used by natives for food and medicine. The “wintergreen” aroma and flavor from the Wintergreen leaves and fruit (and also found in Birch trees) was used for gum, candy, perfumes, hygiene products, teas and other drinks, as well as cleaning products, until scientists figured out how to synthesize it in the laboratory. Since then, Wintergreen has become a significantly less important commercial plant. However, there has been a bit of a resurgence in its popularity due to modern herbalists use and the development of ornamental varieties.
- Plants that stay green through Winter were initially known as Wintergreen, but now the term Evergreen is commonly used.
- While dark and glossy green most of the year, the leaves will turn red or bronze in Autumn.
- The “fruit” (0.25-0.5 inches/6.3-12 mm) is actually a dry capsule surrounding a fleshy calyx – this is part of the flower!
- Oil of Wintergreen is made through steam distillation of the macerated leaves.
- Most of the Oil of Wintergreen available today is synthetic.
- Oil of Wintergreen is about 98% methyl salicylate.
- It is believed that methyl salicylate is released from the plant when attacked by harmful insects and that it attracts beneficial insects to deal with the pests. Note: I have yet to find good research to support this, but if this is true, it is very interesting. Maybe sprinkling Oil of Wintergreen through the garden will bring on an army of beneficial insects??
- The entire genus that Wintergreen belongs, Gaultheria, was named after Dr. Jean-Francois Gaultier, a mid-18th century French physician stationed at the colony of Quebec from 1742-1756. I love learning about naturalist doctors!
- The species name, procumbens, means lying flat. This is an appropriate name for this low-growing shrub.
USING THIS PLANT
- Edible Fruit – These have a classic “wintergreen” flavor… kind of minty, but sweeter. Often rather bland. Can often have a “medicinal” taste to it. Can be eaten raw or cooked. Used in sauces, jams, pies, etc. The seeds need to be strained out.
- Edible Leaves – only the very young leaves are worth eating raw. Really, they are just chewed. There is an initial Wintergreen flavor, and after a few minutes the leaf becomes bitter; then just spit it out.
- Tea Plant – wintergreen-flavored fruits and leaves are used to make tea. It was common enough that the plant is also called Teaberry. But just soaking the dried leaves in hot water (like brewing ordinary black tea) does not produce a tea with the Wintergreen flavor. The key is to slightly ferment the leaves first. Here’s how to do it: Fill a sterilized jar with fresh Wintergreen leaves. If the leaves are mostly red, then the tea will be pink. Then cover it with cool, previously boiled, filtered, or distilled water. Let it sit in a warm place, not in direct sunlight, for a few days. The water will become bubbly as the fermentation takes place. Filter the tea and save the leaves. The tea can be slowly warmed until hot, but not boiling. This tea will have a great Wintergreen flavor! The tea may need to be diluted with additional water if it is too strong. Dry the saved leaves; they can be used for at least one other batch of tea, but it won’t be as strong.
- Essential Oil – This oil can be extracted through steam distillation. It is used in perfumes and fragrances and also as a flavoring agent in candies, gum, toothpaste, alcoholic drinks, etc. This is very strong stuff! See note about toxicity in Concerns below.
- General nectar source (especially bees).
- Ornamental Plant – some varieties have been developed and used mainly for ornamental value.
- Ground Cover – tolerates only a little foot traffic. It is best when combined with another groundcover plant, as Wintergreen grows so low to the ground that many weeds are not suppressed in the early years of growth, before a mat forms. Alternatively, weeding for the first few years could be used if an unmixed groundcover is desired. Plant 10-20 inches (25-50 cm) apart.
- Dynamic Accumulator – when the above-ground portions of this plant dies back, it releases the nutrients it has mined. Wintergreen is known to accumulate magnesium.
- Drought-Tolerant Plant – withstands drought once established.
- Wildlife – Autumn and Winter fruits and browse for deer, bear, ground birds (turkey, grouse, pheasant, etc.), and small mammals (fox, chipmunks, squirrels, mice, etc.)
- Medicinal Plant – The leaves and berries contain methyl salicylate which is very similar to salicylic acid, the active ingredient in aspirin. Many native peoples used the tea (see above) as a pain and fever reliever. The same cautions for using aspirin apply to Wintergreen as a medicinal plant. See note about toxicity in Concerns below.
Harvesting: Fruit is harvested in Autumn-Early Winter. Frost seems to sweeten the fruit a bit. The leaves can be harvested at any time.
Storage: Berries are best used fresh. Leaves and berries can be dried.
DESIGNING WITH THIS PLANT
USDA Hardiness Zone: Zone 3-8
AHS Heat Zone: 8-1
Chill Requirement: Likely considering where this plant originates, but no reliable information is available.
Plant Type: Prostrate (low-growing) Shrub
Leaf Type: Evergreen
Forest Garden Use: Underground Layer, Herbaceous Layer
Cultivars/Varieties: There are a number of cultivars available.
Pollination: Self-fertile. Pollinated by bees.
Life Span: No good information available, but as the plant spreads through rhizomes and stolons, an individual’s life span is likely irrelevant.
PHYSICAL CHARACTERISTICS OF THIS PLANT
Size: 2-6 inches (5-15 cm) tall and indefinitely wide
Roots: Fibrous and shallow with stolons (stems that creep along the ground which can place new roots down) and rhizomes (underground stems that shoot up new plants).
Growth Rate: Slow to Medium
GROWING CONDITIONS FOR THIS PLANT
Light: Prefers full to patial shade, but will produces more fruit in sunny openings with some shade.
Shade: Tolerates deep shade
Moisture: Dry to moist soils.
pH: 4.2-6.5 (prefers more acidic soils)
Special Considerations for Growing:
Consider pairing with other plants if using Wintergreen as a groundcover – see note in Secondary Uses above.
Division is easy and can be done anytime, although early Spring is probably the best. Can be propagated with seed, but requires 4-13 weeks cold-stratification. Seeds germinate in 1-2 months. Also propagated from semi-ripe cuttings.
Toxicity: Methyl salicylate is an organic ester found in a number of plants such as Wintergreen, Birch, and Meadowsweet. It is similar in structure to salicylic acid, the active ingredient in aspirin. Oil of Wintergreen is a highly concentrated form of methyl salicylate. It is reported that 10 milliliters is a fatal dose in a child, and 30 mL will kill an adult; however, there ahve been fatalities with as little as 4 mL (that is just over a teaspoon!). As the methyl salicylate can be absorbed through the skin, even topical use can be dangerous. With all that said, we need to be very careful about when, why, and how we use this essential oil.