Milkweed
Not only butterflies love this plant, it's loved by many foragers. In Spring the shoots can easily be mistaken for Dogbane, a poisonous plant so be cautious! Dogbane has round, solid stems while Milkweed stems are square-ish and hollow. The milkweed buds, flowers and seedpods are also edible.
Click here for photos of Milkweed.
Click here for photos of Milkweed.