Green garlic, as I understand it, is just the new Spring growth, before the bulb has a chance to form - think "green onions", but garlic instead. I've never used them, but have enough in the garden this year that I should, and will. Fennel is nice braised; look for a recipe for braised celery, and use the fennel instead. Or sliced raw in salads. The fronds are perfectly edible; take a taste, and imagine where you might like that flavor. The herb fennel, by the way, that is the plant without the bulb, just the frond like leaves, grows wild all over the coast in N. California; as a N. Californian I'm sure you've seen it, though you might not have known what it was.