Another schizophrenic vegetable, fennel has those thick fleshy bulbs and fine, fine fronds. I choose to separate them when I get the fennel home. Bulbs get store, unwashed, in the refrigerator and fronds get rinsed, dried and then wrapped in a dish towel to use pretty quickly. The fronds will eventually start to wilt, but they’ll be good for a few days. The bulb can keep for a week or two. If you’re not using the fronds in a salad or as a garnish for your cooked fennel bulb dish, consider making pesto.