Smoke Catalpa Pods Catalpa (Catalpa speciosa) The Northern Catalpa Tree Extension Catalpa Bates Canopy Bates College Northern Catalpa (Catalpa speciosa) MyGardenLife 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 10 Benefits of Having a Northern Catalpa 10 Benefits of Having a Northern Catalpa