What are winter onions?

"Winter onion" is a general term used to describe onions that can survive the winter outdoors in the ground.  The Egyptian onion (also called tree onion and walking onion) produces clusters of small bulbs (called bulblets) at the tops of flower-like stalks in summer.  Eventually, the stalk falls to the ground, allowing the bulblets to root.  This unusual reproductive method allows the plant to “walk” around the garden.  Egyptian onions are used primarily for green onions.  Multiplier onions (also called potato onions) divide underground forming clusters of small to medium-sized bulbs.  Multiplier onions are grown for green onions or mature bulbs.  In Iowa, fall planted multiplier onions should be mulched in late November to help them survive the winter.  Both the Egyptian onion and multiplier onion are sometimes referred to as winter onions.