Though these flowers lean more toward summer blooming, some do bloom in the spring. While calling any flower "the best one" is like picking a favorite child, we can't help but favor these. Of the many varieties of allium, some grow to an exuberant 4 feet in height and have perfectly round blooms up to 5 inches wide in a jazzy array of blues, purples and pinks. If there were ever real-life flowers that sprang from the imagination of Dr. Seuss, they would be giant allium blooms. Secondly, the Allium genus harbors a secret disguised by their beauty; they are the very plants that give us onions, garlic, chives, leeks and the like. The flower equivalent of beauty and brains ... that's just the best.