Without the Prussians, Frankfurt most likely would never have had its Palmengarten. Its foundation in 1868 ows itself to a predicament – and a daring citizens initiative. The Duke Adolph of Nassau was in a financial tie. His castle gardens in Wiesbaden-Biebrich comprised 200 exotic plants. In the course of annexation of the duchy along with the city of Frankfurt by Prussia in 1866, the botanically inclined duke was forced to sell his famous “Biebricher Winter Gardens” and asked Heinrich Siesmayer (1817–1900) for assistance.
Siesmayer was a renowned horticulturist who had, among others, conceptionalized the Bad Nauheim Kurpark. The duke’s collection seemed to allow him to implement a long-held dream: similar to Brussels and London, Siesmayer intended to create a “Southern Palace” in Frankfurt – an exotic garden with social events. What he needed was supporters and money. Both were eventually supplied by a handful of honorable citizens and businessmen, among them Leopold Sonnemann, banker and founder of the former “Frankfurter Zeitung”. In May of 1868 a committee was formed to purchase the “Biebricher Wintergärten”. The issued stock shares were so popular that very shortly after their emission the valuable plant collection could be acquired from Adolph of Nassau for 60,000 Rhein-Gulders.
The City of Frankfurt made available a slot of some 18 acres along the rural Bockenheimer Straße to the joint-stock company as an hereditary tenancy. The greenhouses were erected in 1869 and the first flower show took place in 1870. The official inauguration of the magnificent gardens with Palmenhaus and adjoining building for socio-cultural events was celebrated on March 16, 1871 in the presence of the Prussian Crown Prince. And three years later it was the Emperor Wilhelm I himself to honor the splendid Frankfurt Palmengarten by a personal visit. Its exotic plants as well as concerts and balls soon made the Palmengarten a highly attractive center of social life in the city.
The era of initiation ended in 1886 with the retirement of Heinrich Siesmayer as honorary director. His successor August Siebert (1854–1923), a renowned horticultural expert in respected social standing, was able to expand and improve the gardens considerabley within the four decades of his leadership. Among others he established new greenhouses and a rosary, introduced electricity, and published a first printed guidebook. In times of distress during World War I, the greenhouses and grounds served as vegetable plots to supply military hospitals. As part of the meanwhile highly prestigious Westend, the gardens managed to be maintained during the war, while the following economic crisis required major readjustments.