Racism aside, your statement is plain not true.
Large-scale islamic immigration into Germany started back in 1961 with the signing of a labour agreement between West Germany and Turkey. West Germany did not have enough people to fulfil the cheap, labour intensive jobs that even jobless Germans did not want. Konrad Adenauer was then the Chancellor. The Turkish community in Germany is the largest outside Turkey and the Turkish language is the second most spoken language after German. Estimates are at least 4 million Turks in the country. In 2000 under Chancellor Kohl, immigrants born outside Germany could apply for German citizenship if they had lived in the country for 8 years. Before Syrian refugees were permitted entrance to the country, Germany had 3,000 mosques.
Odd how 5,720,000 Muslims live and work in France. 2,660,000 foreign born Muslims live in Britain. In total an estimated 19 Muslims live in the EU. I fail to understand how Mrs. Merkel bears responsibility for what you call a disaster!