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 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 Polk Salad Annie Northern Catalpa Catalpa Speciosa Deciduous Trees Cold Stream Farm