Northern Catalpa Catalpa Speciosa Deciduous Trees Cold Stream Farm Tree Tales: Call of the Catalpa Go Green Brooklyn Northern Catalpa Ohio Department of Natural Resources The Northern Catalpa Tree Extension 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 Biography of Durham's Finest Tree* No. 10: Parkwood Southern Catalpa ( Catalpa bignonioides) Extension Master Gardener Volunteers of Durham County