Otto Brandmuller was born in Germany and trained as a horticulturist, he left the Prussian army into which he had been drafted to come to South Africa in 1890. His first two years here were spent traveling South Africa and hunting wild animals to ship to zoos in Europe. In 1893 he was appointed by Sammy Marks to begin the afforestation of the dry veld area on the Free State side of the Vaal River. He planted oak trees (from the acorns gathered from the Pistorius oak trees) and pine trees (mostly the Pinus Insignius and Pinus Pinaster varieties) to create a magnificient forest at Maccauvlei. In 1912, Otto began to beautify the banks of the Vaal River, planting willow and popular trees. This helped to make the Vaal River become one of the most popular scenic pleasure resorts in South Africa.
Otto Brandmuller spent 44 years planting trees and it was estimated that when he died, at the age of 92, he had planted more than six million trees. His son, Ernest took over as forester and horticulturist and today the Brandmullers are still one of the leading nurseries in the Vaal Triangle. In total, Otto and his son planted 4 000 acres of forest and 28 000 apple trees, the apples being exported to Covent Garden. The area soon became known as the apple belt.
In 1936 he bought a 440-hectare farm called Varkensfontein on the border of Walker’s fruit farms in De Deur and established a wholesale nursery, now known as Arboretum (latin for trees). He left his farm to his four children Ernest, Dorothy, Elsie and Harold, and it is Harold’s daughter, Karen, who is now running the nursery.
In February 1998 Karen developed the old milk room and mielie meal store into a modern overnight bed and breakfast and in the following year established a bush camp accommodating 30 people. The camp was named Thabeng derived from the Sotho word thaba. In April 2001, 3 hiking trails were developed through various types of habitat including grassland, thorn tree bush, Blue gum and Pine forests.