Common Milkweed (Asclepias syriaca), a native perennial typically found growing in colonies, offers several different wild vegetables, depending on the season. In June and early July, the flower buds appear at or near the tops of plants, and these fuzzy green clusters can be gathered for food. I take no more than half the clusters per plant, making sure to leave plenty to flower and produce fruit. Foragers will notice that milky sap oozes from detached bud clusters.
I boil the buds for 5-10 minutes, drain, and enjoy. Acclaimed forager and author, Sam Thayer, says they can also be steamed whole or diced up and stir-fried. Open flowers can also be cooked and eaten, but I've not yet tried them. If you've sampled the buds or open flowers, I'd be curious to hear your experience.
Note: While there are other Milkweed species (Asclepias genus) in New England, Common Milkweed (A. syriaca) is the only one I know to be edible.