Pomaderris kumeraho or kumarahou, also known as gumdigger's soap, is a plant endemic to the North Island of New Zealand. The name kumarahou is derived from a Maori word, signifying a shrub.Kumarahou grows up to four meters in height, and flowers in September, with yellow blossoms. The name "Gumdigger's soap" was given owing to the lather created when the flowers were rubbed with water.