[3] He was joined in London by his younger brother John Ruddenklau (Johannes Rüddenklau; 30 August 1834 – 16 May 1896),[2][7] who worked there for some years before returning to Germany.

John Ruddenklau, who had also trained as a baker, emigrated to New Zealand in 1856, and arrived in Lyttelton on the Joseph Fletcher in October 1856.

Historian George Macdonald has recorded that they arrived by the Bosworth,[9] but the passenger list published by the Lyttelton Times on 23 December 1857 mentions his wife and daughter only.

[19][20] Yet another fire occurred in pretty much the same location in June 1867 and this time, the heat caused damage to Ruddenklau's building.

[22] In December 1864, a gas network was installed in Christchurch, and the City Hotel was one of the first premises that made use of the new source of light.

[23] Only two months later, Ruddenklau had to defend a breach of the Public House Ordinance for failing to keep the entrance lamp of his hotel lit during the prescribed hours.

On this occasion, the proprietor got cautioned by the resident magistrate Charles Bowen,[24] but in September 1866, he was fined NZ£1 for the same offence.

He engaged his fellow Christchurch city councillor, architect Samuel Farr, to design an adjacent brick building facing Colombo Street.

Upstairs, a billiard room was fitted with a table acquired from John Thomas Peacock, one of the richest people in Christchurch.

[26][27][28] In 1867, Ruddenklau was one of the founders of the Canterbury Brewing, Malting and Distilling Company that was to be chaired and directed by George Oram, the eldest of five brothers working in the hotel industry.

[32][33] With those objectives closely related to religion, it wasn't long before it was proposed to build a church for German Protestants.

Funds were raised by a committee presided by Ruddenklau, and in November 1872, the foundation stone of the German Church was laid.

[32] Ruddenklau travelled to Germany in February 1873[34][35] and among other duties, he found a pastor and arranged transport for the three bells that the church building committee had requested from the German Chancellor, Otto von Bismarck.

[43] Five people contested the four available positions, and Ruddenklau came fourth and was thus successful, just one vote ahead of the person who came last.

[49][50] James Gapes announced on 25 November 1881 his candidacy for a third term as mayor, as he was not satisfied with the other two contenders for the position, the timber merchant Charles Benjamin Taylor,[51] and Ruddenklau.

[61] One of the last public duties carried out by Ruddenklau was to open the Armagh Street Bridge on 11 December 1883.

Speeches at the opening were given by Mayor Ruddenklau, Mayor-elect Charles Hulbert, and senior councillor Aaron Ayers.

Ruddenklau Lane in the Christchurch suburb of Bishopdale was created in a subdivision in the early 1980s and runs alongside the headwater of Dudley Creek.