[1] Holtze studied at Hildesheim and Osnabrück before serving an apprenticeship in Hanover, where he subsequently worked for four years in the Royal Gardens.
[2] Holtze sent a large number of botanic specimens from the Darwin area and nearby islands, many of which had not been previously described, to Ferdinand von Mueller.
In Adelaide, succeeding the great Dr Schomburgk as curator, he did much to make the Botanic Gardens an attractive place for the general public to visit, a novel policy at the time.
[4] He is buried in the Penneshaw Cemetery on Kangaroo Island along with his wife, Evlampia (née Mizinzoff), who died 5 July 1937.
[5] A son, Alexis Leopold Holtze (1883 – 26 November 1938), was horticultural correspondent for the Mount Barker Courier, and editor of Garden and Field,[6] later manager of radio station 5AD.