The extensive park was started in 1891 by the great dendrologist Maximilian von Sivers. He chose a 16 ha area on the lower and upper terraces of the Daugava bank, where there is a sufficient variety of terrain. On the upper terrace, the dolomite layer is covered in some places by a relatively thin layer of 10-30 cm, so a hole was dug in the dolomite, filled with dirt or peat, clay or gravel was added and irrigation lines were laid. As early as 1881, seeds were sent to Sivers by post, and in the spring of 1882, the first nurseries - lecektis - were set up inside the Old Castle's dolomite fence. The first planting in the arboretum began in the spring of 1891. In 1899, 451 species of woody plants grew in the park's exposition; 15 years later, 590 species had already been planted. The park has a variety of woody plant species from all over the temperate zone of the northern hemisphere. The park used to be divided into 19 floristic geographical areas. Today, around 250 of what were once different tree species can be seen in the park. The castle staircase, a stone card table, a tea terrace, a fountain and the ruins of the castle farm have been preserved. The area is managed by JSC ‘Latvia's State Forests’.