To be honest, I've never gave a thought to what they're grown from. I just know how it looks and tastes LOL. And I love it. And the rest of my family too.
Here's pics with it if the link above doesn't work.:
And here it says what green garlic is: immature garlic harvested before it matures:
http://www.organicauthority.co...
http://www.wisegeek.com/what-i...
http://www.saveur.com/article/...
And here about garlic scapes:
http://gardening.about.com/od/...
"Garlic scapes are the "flower stalks" of hardneck garlic plants, although they do not produce flowers. These stalks start to appear a month or so after the first leaves. They are usually cut off of the plant, since leaving them on only diverts the plants strength away from forming a plump bulb. If left on, they eventually form small bulbils that can be planted to grow more garlic, but it takes 2–3 years for them to form large bulbs. Many gardeners simply toss their scapes in the compost, but garlic scapes are both edible and delicious, as are the bulbils.
Along the same lines,
young garlic plants that are pulled to thin a row are referred to as "green garlic". Used in the same manner as green onions, these too make excellent eating."
And pics of garlic scapes:
It is not a waste of the garlic to harvest it younger. This is all its charm, being that way, not as spicy as the mature garlic but at the same time so tasty and crunchy. There are some recipes that cannot be properly done without green garlic.