The easiest way to understand the difference between spring garlic and garlic scapes is to think about the life cycle of the hardneck garlic. When the garlic is harvested while it is young and the bulbs have not fully formed, it is called spring garlic or green garlic.
Spring garlic tastes and smells like regular garlic but in a more delicate way. Both the partially formed bulb and leaves are edible.
How to use spring garlic
How the bulbs are prepared for cooking depends on how premature they are. Really premature ones can be sliced and cooked directly. If segments have formed, the paper-like layer that covers them may have to be removed depending on how thick they are.
The leaves resemble scallions and can be cooked the way you would cook scallions.
If the garlic is not harvested prematurely and allowed to continue growing, stalks form above the soil. The stalks curl as they grow and form an elongated bud at the tip. The stalks are normally harvested before the buds form.
These stalks, called garlic stalks or garlic scapes, are often cut off because of the belief that they compete for nutrients and stagnates the growth of the bulbs under the soil. The stalks, or scapes, are very flavorful.
How to use garlic scapes
Unlike the leaves of spring garlic (which are real leaves), garlic scapes are stalks in the truest sense of the word. In appearance, they look like shorter and smoother yard-long beans. In texture, they are similar to asparagus. When cooked properly, they are lightly crisp and delicately flavored.
From the New York Times’ Melissa Clark:
Unlike regular garlic, which needs some kind of vehicle to carry its intense flavor to the mouth, scapes are self-sufficient; vegetable and aromatic all in one. Ever since that first batch, I gleefully buy scapes whenever I can, using them in salads, soups and pesto.
Garlic scapes are especially wonderful in stir fries. Instead of having to mince garlic and prepping greens, you just cut the garlic scapes into the desired length and you get the best of both worlds — substantial greens AND a delicate garlicky flavor.