Northern Catalpa (Catalpa speciosa) organically grown flower seeds. Floral Encounters. In autumn, mature catalpa seed pods turn brown and often hang on the tree through late fall and into winter. Today's @marthastewartblog looks at some of the seeds, berries, and cones of Southern Catalpa (Catalpa bignonioides): Essential Guide Meet My Nature Neighbor: The Catalpa Tree Heartspoken How Good Is Catalpa Firewood? Axe Adviser Northern Catalpa Ohio Department of Natural Resources