While catalpa trees are not generally considered highly toxic, some parts of the tree, particularly the roots, are known to be poisonous according to the USDA Plants Database. The leaves and seed pods Catalpa Trees Have Roots Dating Back To Early Severna Park Severna Park Catalpa: Care and Growing Guide While catalpa trees are not generally considered highly toxic, some parts of the tree, particularly the roots, are known to be poisonous according to the USDA Plants Database. The leaves and seed Polk Salad Annie