Franklin & Marshall Northern Catalpa (Catalpa speciosa) The Beautiful Catalpa Tree, Huge Flowers and Fishing Bait Hudson Valley Gardens Catalpa speciosa #3 (Northern Catalpa) Scioto Gardens Nursery Catalpa Tree Pods Smoke Northern Catalpa No these aren't giant tree green beans, but instead the seed pod of the northern catalpa. These bean like pods can grow to be 20" long and contain numerous 1" long seeds. #haverfordcollegearboretum # Southern Catalpa (Catalpa bignonioides): Essential Guide