Good King Henry is a perennial vegetable closely related to spinach that produces delicious green shoots in early spring and succulent leaves in late spring and summer.  In a partly shady location with moist and rich soil in summer, you'll have more greens than if you had planted spinach, and a plant that gets bigger instead of dying each year.  Although some like it raw, I find the uncooked leaves too astringent.  Cooked like spinach, on the other hand, they are delectable.