Allium x proliferum - Aka-Tree Onion, Walking Onion, Egyptian Tree Onion. Perennial onion. Full sun to part shade, but prefers full sun. Propagates itself by forming bulbils on top of a green stem, the stem bends over with the weight of the bulbils, which grow into new plants once they touch the ground. A good cold hardy onion, surviving even in frozen ground. Blue green leaves. The whole plant can be eaten, even the bulbils. If the onions are not harvested, they will divide and grow into more plants. When harvesting green tops, only harvest a couple at a time from each plant, new leaves will grow to replace the harvested ones. A really productive and hardy plant for the vegetable garden.