After harvesting the seeds from the Plumeria seedpod, you can discard the empty seedpod. If the seedpod has not split open naturally, it is a sign that the seeds inside were not fully developed and viable for propagation. In such cases, it is best to remove and discard the unopened seedpod. Proper disposal of the empty seedpod prevents any potential fungal or pest issues and keeps the planting area clean. Focus on storing the harvested seeds properly in a cool, dry location for future planting or propagation.