I got my wife and kids eatin poke about 4 years ago. Definitely, only use the youngest of sprouts in spring, like shin high. Cut with scissors. We use the small stems like asparagus---remove the leaves (cook later, differently), and put the stems in a glass pan, with some melted butter, little water to make steam, and salt/pepper. Bake in the oven til tender.
Take the leaves and cook like spinach. We don't dump the water, trying to keep the nutrition, but it will give you a funny aftertaste on your teeth. I read it is VERY high in vitamin A, almost to the point of toxicity, if you have too much, and I suspect that is the source of the aftertaste. Our kids call it "chokeweed," but they eat whatever we put in front of them. We eat some, and freeze what we have cooked extra, for later in the year. This is probably the one thing we get from the wild we eat the most of in a year.