The term POISON SHRUB can be summarized as a shrub that is poisonous. SUMAC (5 letters) is a type of poison shrub that is native to North America and parts of Asia. It is a deciduous shrub that can grow up to 10 feet tall and has compound leaves with serrated leaflets. The plant produces small, red-brown fruits that contain a toxic oil. Ingesting the oil can cause severe irritation to the skin and mucous membranes.