Purple goosefoot, also known as magenta spreen, is a variety of giant pigweed (Chenopodium giganteum, Family Amaranthaceae which includes familiar vegetables such as chard, beets, and spinach and the pseudo-grains quinoa and amaranth). It is an annual growing to six or even eight feet with a spread as much as three feet. The stalk can be two inches in diameter.
Purple goosefoot is now well established in my gardens having been introduced there from a packet of seeds 12 years ago. The purpose that year was to grow an edible green and purple goosefoot is very edible and very nutritious. I let some plants flower and go to seed. Pigweed and goosefoot can make anywhere from 100,000 to 1,000,000 seeds per plant and the seeds can live in the soil for decades. Now I don’t need to buy seeds anymore and every year thousands of plants sprout up.
The whole plant is edible but the best parts are the tender new growth at the tips of branches. If the stem is soft enough for your fingernails to cut then it is soft enough to eat. I pinch off the tender growth into a large bowl, rinse it with water, and steam in a covered skillet until the leaves wilt. The taste is a bit like chard and spinach. Most years the harvest is large enough so that several large packs can be put into the freezer for winter use.
Purple goosefoot is a prolific plant and it soon grows faster than I can harvest. This is not a problem and the tall coarser plants make good sheep feed if mixed with grasses. Many chenopodiums are larval host plants for a variety of moths and butterflies such as the common sooty-wing. Clumps of ripe stalks left standing in the winter provide shelter and food for small birds who feast on the seeds. Birds I have seen feeding in clumps of pigweed are chickadees and pine siskins.