Pot Marigold (Calendula officinalis) is a plant with a rich history. Beloved in cottage and country gardens since Medieval times, it bears cheery, bright-yellow-and-orange flowers. (The petals were once used to color butter.) Not a true marigold (species Tagetes), it grows to 2 feet tall and blooms from spring to fall. The edible petals have an aromatic bitterness said to complement soups and salads. Decoctions made with the petals have been used for medicinal purposes as well.