Last year I bought an amaranth plant. I can't remember what kind it was, but it was sold as an edible. It never got more than about 18 inches high, but it had great red leaves and tassel-like flowers. It also re-seeded freely and I've got a number of new sprouts already growing.
But I got some seeds a couple years ago for the old-fashioned Amaranthus caudatus, better known as Love Lies Bleeding. I tried sowing them but nothing came up, and once again I'm suspecting that it's because I didn't keep them watered well enough. So I'm giving it another try. I'm planting them against the south fence, where I think they'll get enough sun. The seeds are very tiny and I sprinkled them about with a pretty liberal hand. Hopefully, something will grow. I love that this plant is both ornamental and edible. Double-duty is a very noble thing for a plant to do.