Pomaderris kumeraho or kūmarahou, also known as gumdigger's soap and golden tainui, is a plant endemic to the North Island of New Zealand. The name kūmarahou is a Māori word signifying a shrub. Kūmarahou 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.