Egyptian Walking Onions will walk right across your yard and keep giving you onions forever without your help!
In the ground, the Egyptian Walking Onion plant produces a small shallot-like onion which can be harvested. Once harvested, however, the plant will not grow back. If left in the ground, the onion will produce shoots on which the end will form a cluster of onion bulbs. New shoots and topsets will grow from the onions each year which fall over from the weight in the fall where the new bulb roots and it starts all over again!Egyptian Walking Onions are perennial plants and will grow back each year and yield new and bigger clusters of sets on the top and new onion offsets in the soil - they will divide. During their first year of growth they will not produce topsets. You might see only greens. But don't be disappointed, your Egyptian Walking Onion plants will grow back the following year in full force and produce their first clusters of topsets. Once established, plants may be propagated by division or by planting the sets that grow from the top. Egyptian Walking Onions are extremely hardy plants that grow well in zones 3-9.
egyptianwalkingonion.com/ for lots of great information.