Johann Wilhelm Weinmann, pharmacist and botanist, was born on March 13, 1683 at Gardelegen, Germany, the son of a barber, Matthias Christian Weinmann. Little is known about his early life, but he settled in Regensburg in 1710 as a pharmacist’s assistant in a local apothecary shop. He later made the claim that he had worked with physicians and apothecaries in many German towns and that all of them would give favorable testimonials in his behalf. What is certain is that Weinmann’s fortunes developed rapidly in Regensburg. In 1712, he was able, with his fiancée, to purchase a house and apothecary shop; his bride, Isabella Catharina Fürst, was the daughter of a well-to-do wine merchant. In 1732, two years after the death of his first wife, Weinmann married Christine Catharina Pfaffenreuther, the daughter of a town official, and was able to purchase a bankrupt pharmacy business which he soon built up into a thriving concern.

Shortly after his first marriage, Weinmann became involved in a series of disputes with other pharmacists and some of the town physicians; these arose out of his official position as Hospital Apothecary to which he had been appointed in 1713. The quarrels among the various parties eventually became so disruptive that, in 1715, the Town Council was forced to intervene and Weinmann was officially censured for his actions. At the same time, the physicians involved were ordered not to interfere with him in his professional activities.

This affair had no long lasting effect on Weinmann’s career. In 1722, he became a member of one of the town’s councils, from 1725 to 1733, he was a commercial assessor, and from 1733 to 1740, he held the post of city assessor. At the same time, his business enterprises were flourishing, he had become a wealthy man, and these favorable circumstances permitted him to indulge in his much desired avocation-botany. He established a small botanical garden in Regensburg and, in 1723, published a brief work entitled Catalogus Alphabetico ordine exhibens Pharmaca .... He also contributed botanical notes as "Observationes und Anmerkungen" in the "Breslauer Sammlungen".

Weinmann’s major creation was Phytanthoza iconographia (1737-1745), a great project which comprised eight folio volumes with over a thousand hand-colored engravings of several thousand plants. The first artist employed by Weinmann was none other than Georg Dionysius Ehret (1708-1770) who would become one of the foremost floral illustrators of the eighteenth century. When he was introduced to Weinmann in 1728, he had no employment and was so poor that he had not been able to pay his river passage from Ulm to Regensburg, but had worked it off by taking turns at the oars. When Weinmann saw examples of Ehret’s work, he hired him to draw a thousand illustrations in a year’s time for which he would be paid fifty thaler. He was also given room and board and lived in the Weinmann house with the apothecary apprentices. At the end of a year, the artist had completed half of the assignment, and Weinmann, claiming that the contract was unfulfilled, gave him twenty thaler and sent him on his way. Several years later, Ehret brought a suit against his former employer in order to obtain compensation, but Weinmann claimed that Ehret had deserted him, and the suit failed. In spite of these early difficulties, the latter’s career was filled with success stories on the Continent and in England where he had many wealthy patrons.

After Ehret’s departure, Weinmann hired other illustrators and engravers, and the text was the work of the Regensburg physician, Dr. Johann Georg Nicolaus Dieterichs. Phytanthoza iconographia was published in both Latin and German editions, and a Dutch edition appeared in four volumes in 1736-1748. This edition was brought to Japan in the early nineteenth century, and some of the Weinmann illustrations were the source for those in Honzô zufu, the monumental Japanese botanical work by Iwasaki Tsunemasa (1786-1842). This book, which describes and illustrates 2000 plants, is said to be one of the two most important treatises on systematic botany in the Tokugawa period (1603-1867).

Weinmann’s great work has been described in various ways, not all of them complimentary. It is acknowledged that Phytanthoza was impressive for its size and scope, but criticisms were made concerning some of the plant specimens displayed. The German botanist, Christoph Jakob Trew (1695-1769), who was a friend and collaborator with Georg Ehret for thirty-six years, wrote to a friend in 1742-"... it is really regrettable that the late Weinmann’s precious work had so many untrue, even faked images which gave it a bad name with those who are knowledgeable...." It is also unfortunate that Weinmann employed a number of illustrators who, unlike Ehret, had little or no knowledge of botany. Wilfrid Blunt, in The Art of Botanical Illustration, described the volumes more impressive in size than in quality, but "certainly a memorable achievment".
 

Robert F. Erickson