With William I, Elector of Hesse, she had eight children, seven of whom lived to adulthood:
- Wilhelm Karl von Haynau (24 December 1779 – 21 January 1856)
- George Wilhelm von Haynau (27 February 1781 – February 1813)
- Philipp Ludway von Haynau (18 May 1782 – 5 June 1843)
- Wilhelmine von Haynau (20 July 1783 – 27 May 1866)
- Moritz von Haynau (4 July 1784 – 9 September 1812)
- Marie Sophie von Haynau (11 September 1785 – 21 April 1865)
- Julius Jacob von Haynau (14 October 1786 – 14 March 1853)
- Otto von Haynau (12 June 1788 – before 24 May 1792), died in childhood
The surviving children were all legitimized on 10 March 1800 and made Barons of Haynau.
In 1788, William hypocritically accused Rosa, who had been constantly pregnant with his children for most of the last decade, of infidelity and banished her to Babenhausen Castle. He replaced her with Karoline von Schlotheim. There, on 13 February 1794, Rosa married her guardian, Johann Georg Kleinhans (d. 17 February 1835), who later became Councilor of the Grand Duchy of Hesse, and was thereby released.
