About the Plant
Allium is one of those plants that makes everyone take notice. Even if you are not really into plants and all gardens look the same to you, its hard not to get grabbed by this plant when its in bloom. I notice that kids particulary like this plant, maybe because it looks like something from Willy Wonka and the Chocolate Factory, an amazingly bright purple puff sitting on a thin stalk that can get up to 4' high. Whether you're a child or just a child at heart, Allium is a great bulb for your garden
Species or Cultivars
Go with the traditional Allium giganteum, or Giant Onion. The purple florets blossom into 6-inch plus balls on top of 3-4' high stems.
Allium needs pretty much full sun, I can already see the ones around Brooklyn blooming that are planted in direct sunlight. Its best to plant these as bulbs in late fall and plant a bunch of them. After the second blooming season, the bulb will split and now you'll have two!