According to Genealogy SA, there are these births to a father Herman(n) (von) DITTMER.
1861 David William (Van DITMER) Nairne 22/633
1862 Hermann Nairne 24/236
1863 August Nairne 29/585
1865 Gustav Nairne 36/185
1870 Henry Julius DETTMER (father Hermann Heinrich DETTMER - Adelaide 84/199) -

(death for an Albert DITTMER 1871 - Adelaide 40/427)
1872 Mary Josephine Adelaide 109/207
1874 Theodor Joseph Adelaide 135/157
1876 Arnold Adelaide 163/485
1877 Oswald (von DITTMAR) Adelaide 188/204
1881 Catherine Wilhelmine Adelaide 257/125
1885 Eva May Morphett Vale 350/335
1890 Mary Alice Evelyn Encounter Bay 467/243
1892 Herbert John Strathalbyn 512/214
1895 Florence Elizabeth Encounter Bay 561/154
Obviously some of these later children are probably grandchildren of Hermann and Alice (nee MANNIX). Son Hermann married in 1884, so I suspect the later 4 children are his.
There must also be some other births not found - as Sue says, Alice's obit mentions 10 children. John Leopold von DITTMER is described as the "5th son" in his marriage notices eg
https://trove.nla.gov.au/newspaper/article/48539110
He had a son, Francis Christopher von Dittmer, born in Australia 1864
He also had a son, Francis von Dittmer was born 19th June 1887 in Australia
Francis Albert von DITTMER born 1887 has father Francis von DITTMER (Adelaide 398/129)
Herman R.J. von Dittmer 1832-1897 emmigrated to Australia in 1857. (did he marry in Australia)?
As reply #5 - "Did Herman von DITTMER marry Alice MANNIX in Mount Barker, SA on 6 Aug 1860? His father is named Ferdinand David von DITTMER (her's William MANNIX)."