The trumpet vine (Campsis radicans) is a prolific, deciduous woody vine native to eastern North America. It is famous for its large, showy, trumpet-shaped flowers that attract hummingbirds throughout the summer. Following the bloom period, the vine develops unique reproductive structures that house the seeds, providing insight into how this plant successfully colonizes new areas.
Identifying the Seed Pods
Following the summer bloom, the trumpet vine forms large, specialized seed capsules. These structures hang from the vine, resembling long, skinny green beans or cigars, and typically measure 3 to 6 inches (7.5 to 15 centimeters) in length.
Initially, the pods are firm and green while the seeds mature during late summer and early fall. As the weather cools, the pods lose moisture, turning hard, woody, and medium brown. This transformation signals that the thousands of tiny seeds are ready for release. The mature pod is a dehiscent capsule, splitting open along two distinct seams running lengthwise.
Detailed Description of the Seeds
The individual seeds are numerous, small, thin, and flat, designed to maximize surface area while minimizing weight. The central body, which contains the embryo, is a tiny, slightly darker brown disc.
The most distinguishing feature is the papery, translucent wing that completely encircles the central body. This fine membrane dramatically increases the seed’s overall diameter, giving it an almost circular or slightly oblong shape. The overall color is light to medium brown, with the wings often appearing lighter and more brittle than the core.
When viewed closely, the seeds feel delicate, much like thin tissue paper. This winged structure is an evolutionary adaptation for efficient dispersal. Each mature pod contains hundreds of these lightweight seeds, ready to be carried away from the parent plant.
Natural Seed Dispersal
The release of trumpet vine seeds is timed to occur when environmental conditions favor long-distance transport. The woody capsules remain closed through the fall and typically split open during late autumn or winter months, sometimes persisting on the vine until spring. This timing ensures the seeds are released into the strong, dry winds common during these seasons.
The lightweight, papery wing acts as a miniature parachute or propeller. This structure harnesses the air currents, allowing the seeds to flutter and be carried significant distances away from the parent vine. While the trumpet vine is known for its spread through underground runners and root suckers, the wind-dispersed seeds are the primary mechanism for colonizing new areas.