Garlic scapes are the flowering stalk that grows out of hardneck garlic plants in early summer. After they are harvested, the plant starts directing its energy to growing a nice big bulb, which is harvested a few weeks later (and it the widely recognized part of the garlic plant). Garlic scapes are a great way to add garlicky flavor to a dish, though a bit less pungent than the garlic bulb.
How to Store: Treat garlic scapes like cut flowers, since that's basically what they are. So, wrap the base in a damp paper towel or put it in a glass of water in the fridge. You can also just stick them in a bag in the refrigerator and they'll last for 2-3 weeks that way.
How to Use: Stick them in a salad, pickle them, use them instead of garlic when you cook.