My mother's maiden name is Gerstenslager. By some odd coincidence I am living in the city of Wiesbaden, which is also in the Hessen region. I have yet to meet a Gerstenschlaeger.
FYI, Gerstenschlaeger means singer/musician from the town of Gersten which is named after barley plants. Hesse is in the middle of Germany (slightly to the South and West) and Gersten is in the state of Lower Saxony, which is in the North-west part.
Of course Germany, being a big beer community, has other places with gersten in the name - such as Gerstenberg. I could see a barley farmer from anywhere start a rock band and bam, they have a new name.
Here's a wiki link with the Gersten city coat-of-armshttp://translate.google.com/translate?hl=en&sl=de&u=...