Leeks are flavorful, nutritious and easier to digest than their onion cousins. They're also easy to grow, tolerant of cold weather. As they are very expensive to buy in the grocery store, why not add them to your vegetable garden. With their compact, bolt upright growth, leeks are the ideal crop to squeeze into bare patches. The leaves are also rather ornamental, so why not tuck some into your flower garden for some interesting green texture.