Pokeweed is a very distinctive, succulent plant here on Cape Cod. Its 1/4″ flowers are racemes with 5 white to pinkish round waxy sepals and green centers. Its leaves are large and egg-shaped. The stems turn red with age and the berries turn a dark blue.
It is a large plant which grows from 4-10 feet and blooms from July to September in open woods and fields. I saw these Pokeweeds at Fort Hill in Eastham along the side of the trail by the Nauset Marsh.
In the first photograph you can see the buds before they bloom to the left and as they bloom on the right. In the 2nd photograph you can see the dark blue berries that hang from the plant and look like grapes.
After reading one of the comments, I realized that Pokeweeds are very toxic plants, both the berries and the stem. Stay far away!