<p>The architecture of perennial plants can be described by organizational units (architectural modules) varying in time. Each module comprises a vegetative and a flowering phase. In most plants, the module coincides with a single season, but in the woody <i>Nerium oleander</i> (Apocynaceae), the inflorescence continues flower production after dormancy. We describe this rare phenomenon by following inflorescence development over several years. Architectural modules of <i>N. oleander</i> start with a vegetative phase developing evergreen leaves which can persist for at least 6 years. Each module produces a terminal thyrse with dichasial (geminiflorous) helicoid cymes. Usually, flowers of three branch orders open per season whereas the buds of the 4th order hibernate. These buds continue the cymose branching pattern in the next season, produce flowers of about three branch orders and finally hibernating buds which repeat the branching pattern in the next season. After 4 to 6 years, inflorescences fade, and new modules arise from the axillary meristems of the module’s distal leaves. Perennial inflorescences are rare in non-cauliflorous plants. <i>Nerium oleander</i> represents a novel example to the known diversity of woody plant architecture. It extremely extends the reproductive phase of the architectural module thereby flowering throughout several years with minimal investment costs. Leaf persistence appears to be the most important precondition to evolve perennial inflorescences based on heterochronic processes.</p>