Although mental illnesses have existed ever since the dawn of time, the development of psychiatry is dated to have begun from the end 18th century. At the turn of the 18th and 19th centuries, mentally ill people began to be placed at mental facilities not only to be exercised care of, but also to have their health states improved. The movement of reformation expanded across entire Europe. The Kingdom of Prussia was no exception when it came to establishing asylums. Wanting to create the best environmental conditions for the mentally ill possible, all of the complexes of the asylums were designed so that they served therapeutic purposes. One of the vital elements in this regard was the hospital gardens. The said gardens comprised of partially open, decorative green squares, outlined by the fences of the gardens assigned to the individual wards meant for the mentally ill and the utility gardens, where therapy through labor could be exercised. In conformity with the prototypes described above, in the former Province of Posen four asylums were built. The article analyzes the development of gardens within the urban configurations of select hospitals, comparing them to the leading gardens and theoretical configurations described in the specialist literature.