Look for outdoor connoisseur Hank Shaw's book, Hunt, Gather, Cook: Finding the Forgotten Feast, to arrive summer 2011 from Rodale Books. In the meantime, here's a sneak peek from his chapter on gathering wild greens.
I am constantly amazed at just how many edible plants are out there. Many hundreds, just in North America. They're edible, yes, but worth gathering? Worth getting into your car, driving somewhere, and searching for them? That, to me, is a tall order for a plate of greens. Fact is, I rarely leave my yard when I want them.
When I say wild greens, I mean the leaves or stalks of plants that are best eaten cooked. This separates them in my mental calculus from salad greens both wild and domestic (cresses and arugula, for example). Some plants fit into both camps, depending on the time of year.
Your first forays into foraging ought to begin at home, with something familiar, like dandelions. No treks through uncharted wilderness, no danger. The wonderful thing is that wild greens are all around us. Everywhere. Look out the window. I bet you're looking at some now. Even in a big city or a desert--even in winter.
Lamb's-Quarter, Amaranth, and Orach
These are your "money" greens. All appear in late spring and last through autumn, and all bear lots of teeny seeds that can be used as grain; you might know one domestic species--it's called quinoa.
All three plants start as compact seedlings with soft leaves that can be eaten raw, then grow into rather large, sprawling bushes, with tougher leaves that bear a passing resemblance to spinach. And all are excellent substitutes for spinach, but taste better and are more nutritious. You should be able to find them with little trouble between May and September.
Orach, which tends to like seaside areas or alkaline soil, is the easiest to spot, since it has dramatically triangular leaves. Some places call this plant mountain spinach; others, saltbush. Its leaves often actually taste salty, which is a surprise when you consider how bland most greens taste. It will grow to about 3 1/2 feet tall and become a slightly woody shrub.
Amaranth is easily identified by that red tinge in the stalk and in the veins of the leaves. Do not mistake it for pokeweed in the East, as eating the older leaves of pokeweed will send you to the hospital (although pokeweed's young shoots are delicious). Pokeweed stems are a rich, dark purple the color of blueberries; amaranth or pigweed is the same red as in rhubarb. Amaranth leaves are a gentle spear shape, with prominent alternate veins at regular intervals, and plants will grow to 5 feet.
Lamb's-quarter shares the same general look as amaranth and orach, but check out the undersides of the leaves: They should be silvery and slightly fuzzy. And if you drip water on the underside, it looks like a drop of mercury. Pretty cool, eh?