Tree nurseryman Jean Dieudonné Hermans, farmer and municipal receiver of Herk and Berbroek, chose the domain now called Olmenhof and Harlaz to practice his hobby. He tried to make rare and difficult to grow trees thrive here by grafting them onto native rootstocks. This is how his pleasure garden ‘De Concorde’ came into being. The tree nursery was located on the plot between the Olmenhof and the centre. He succeeded in his experiment. Several trees that he planted can still be seen in the park today. Hermans built a small castle in the park between 1810 and 1840, in which he lived. The castle ‘de Pierpont’ now serves as the town hall. The Olmenhof-Harlaz park is fully owned by the municipality and is used as a municipal park with, among other things, a mini golf course and a zoo. It consists of, among other things, ponds, forest, groups of trees and a lawn. The highway from Herk-de-Stad to Sint-Truiden divides the domain into a western part, park Olmenhof, and an eastern part, forest de ‘Harlaz’. The whole is approximately 15 ha in size. The domain ‘Oude boomkwekerij De Pierpont’, as the domain Olmenhof-Harlaz is officially called, was protected as a landscape by Ministerial Decree of 23 March 1987 for reasons of its (natural) scientific, (cultural) historical and aesthetic value.