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 Came across this tree in Hudson, WI that looked like it had giant green beans growing off of it, looked it up and it's called a Northern Catalpa often known as a " Northern Catalpa Catalpa Speciosa Deciduous Trees Cold Stream Farm Northern Catalpa (Catalpa speciosa) MyGardenLife Biography of Durham's Finest Tree* No. 10: Parkwood Southern Catalpa ( Catalpa bignonioides) Extension Master Gardener Volunteers of Durham County How to Choose, Plant, and Grow a Catalpa Tree HGTV