Green garlic is regular garlic harvested in the spring before the scape has begun to show. It’s bright and garlic-y. The stems can be used just like you would a clove and pack a similar punch.
The scapes are the tender stem and flower bud from the garlic plant. I have overheard people looking for these at the market since April. They carry the garlic flavor you would expect from the bulbs, but bring with an herbiness that’s a nice twist. I also think they’re a bit easier to cook with than garlic. I’ve trimmed them down to manageable pieces. Simply slice, and use as you would garlic (figure 2-4 pieces is equal to 1 clove of garlic).