The graduation tower marked ‘Bad Salzuflen Thermalbad’ is one of the town’s landmarks and the longest of its three graduation towers. The walls are made from stacked bundles of blackthorn, which saltwater is channelled over during frost-free weather. It pours down the walls, creating a spray as it runs over the fine blackthorn branches and making for a seaside-like climate nearby.
Now, the tower is used solely for therapeutic purposes, as an open-air inhalatorium. Mineral deposits from the salt water gradually clog up the blackthorn walls, making it necessary to renew them approximately every 15 years – a major undertaking. The graduation towers were originally constructed as part of the salt works between 1770 and 1845 and made the boiling process more efficient. Once it had run down the blackthorn walls several times, the saltwater was refined to the point of saturation by means of evaporation. This reduced the amount of firewood needed for boiling to about a third. The graduation towers are sometimes incorrectly referred to as salt works.
The rose garden was lovingly designed on the basis of a historic model. Located behind the blackthorn wall, it is framed by the graduation towers, the Leopold-Bad spa and the old inhalatorium. It certainly lives up to its name: with more than 3,000 roses and 800 complementary shrubs such as lavender, sage and gypsophila, it offers visitors a stunning display of flowers.