Seeds from Tapioca Tree, Cassava or Manihot dulcis. Cassava is native to South America but is cultivated in tropical and subtropical zones throughout the world. It is one of the most important tropical food crops in the world. The dark green leaves are a foot or more across and have 5-9 lobes. The leaf stems are very long, up to 24 in long and they are red as are the stems. Plants can grow more than 20 ft tall in frostfree regions, but where they die back and regrow in spring they rarely get more than 10 ft. Zones 8-11.