Wintergreen — Wintergreen is a group of plants. Wintergreen once commonly referred to plants that continue photosynthesis (remain green) throughout the winter. The term evergreen is now more commonly used for this characteristic.
Some species of the shrub genus Gaultheria in the closely related family Ericaceae also demonstrate this characteristic and are called wintergreens in North America, the most common generally being the Eastern Teaberry (Gaultheria procumbens). Several genera of herbaceous plants in the family Pyrolaceae, notably Pyrola, Orthilia, Moneses and Chimaphila, demonstrate this characteristic and are also called wintergreens.
Some species of the herbaceous genus Trientalis in the unrelated family Primulaceae are known as ‘Chickweed Wintergreen’.
The Gaultheria species share the common characteristic of producing oil of wintergreen, the chemical methyl salicylate, which gives plants a distinctive ‘medicinal’ smell when bruised. This oil is used in some kinds of chewing gum and candy, as an alternative to the more common peppermint and spearmint oils. It is also a potentially entertaining source of triboluminescence; when mixed with sugar and dried, it gains the tendency to build up electrical charge when ground.
Some species of birch also produce oil of wintergreen, but these deciduous trees are not called wintergreens.