Winter onions represent a unique group within the Allium genus, distinct from the common bulb onion. These plants are valued for their ability to survive cold temperatures and provide fresh, onion-flavored greens at the beginning and end of the growing season. Their hardy nature allows gardeners to harvest them when most other vegetables are dormant. This resilience makes them a productive addition to the garden, especially for those seeking produce during colder months.
Defining Winter Onions and Common Names
The term “winter onion” primarily refers to Allium fistulosum, an Old World species often called the Japanese bunching onion or Welsh onion. This perennial plant is the true botanical basis for the name, characterized by a clumping growth habit and hollow leaves. It is distinct from the common bulb onion, Allium cepa, which is typically grown as an annual for its large, dry bulb. A. fistulosum is frequently sold in markets as a scallion or green onion.
Confusion arises because “winter onion” is also broadly used for other hardy, perennial multiplier types. One notable example is the Egyptian Walking Onion, botanically known as Allium x proliferum, a hybrid also called a tree onion or topset onion. While both are perennial, the Welsh onion produces clusters from the base, whereas the walking onion has a distinctive reproductive method.
Unique Perennial Growth Characteristics
The defining feature of these plants is their perennial nature, which is why they are called “winter” onions. Unlike annual onions that die after one season, these varieties are extremely cold-hardy, with some cultivars of A. fistulosum capable of tolerating temperatures as low as -45°C. This hardiness allows the plant to persist through winter, making it one of the first vegetables to sprout new, edible growth in early spring. They form dense, slowly spreading clumps that multiply by developing new side shoots or offsets from the base.
These onions are non-bulbing or only form a slightly thickened, elongated pseudostem at the base, differentiating them from the large, globe-shaped bulbs of A. cepa. Their foliage consists of hollow, tubular leaves that grow up to 60 centimeters tall, providing a source of continuous harvest. For A. fistulosum, propagation is typically achieved by dividing these established clumps or by planting seeds.
The Egyptian Walking Onion
The Egyptian Walking Onion (A. x proliferum) has a unique propagation method involving topset bulbils. Instead of producing seeds, small, pea-sized bulbs form at the top of the flower stalk. As these bulbils mature and become heavy, the stalk bends over, causing the bulbils to touch the ground and root, effectively “walking” the plant a short distance to establish new clones.
Using Winter Onions in the Kitchen
The flavor profile of winter onions is generally milder and sweeter than pungent, dry bulb onions. The taste is often described as a pleasant cross between chives and common scallions, though flavor can intensify during the warmer summer months. Nearly all parts of these perennial plants are edible.
The bright green tops are the most commonly harvested part, used raw as a garnish or sliced into salads. The white base, or shank, can be chopped and used in cooked dishes like stir-fries, soups, and egg dishes, offering a mild sweetness when quickly sautéed. For the Egyptian Walking Onion, the small topset bulbils are also edible; they can be used like pearl onions or pickled to create a tangy condiment.