I have not planted elephant garlic in the front yard in ten years. The plants continue to produce every year. Mostly from child bulbs on the parent. But sometimes from seeds dispersed from the flower heads.
This year, I harvested about half of the garlic. Wash off the dirt. Dry for an hour or so. Cut off the foliage about a hand-width about the top of the bulb. Store in a cool dry location (pantry, garage, etc)