From Wikipedia, the free encyclopedia.Coprosma robusta, commonly known as karamu, is a flowering plant in the family Rubiaceae. It can survive in many climates, but is most commonly found in coastal areas, lowland forests, or shrublands. Karamu can grow to be around 6 meters tall, and grow leaves up to 12 centimeters long. Karamu is used for a variety of purposes in human culture. The fruit that karamu produces can be eaten, and the shoots of karamu are sometimes used for medical purposes.