It's a pretty antiquated and uncommon turn of phrase - popularised if not actually coined in Walter Scott's 1818 novel [Rob Roy][1]. But (UK) Chambers Dictionary still includes the definition **to set the heather on fire** *- to create a disturbance or a sensation*.

Today we usually say [set the world on fire][2] (or maybe the also uncommon [sets [one's] hair on fire][3], for things which only disturb/excite one or a relatively small number of people).


  [1]: http://books.google.co.uk/books?id=h_QNAAAAQAAJ&pg=PA234&dq=%22set%20the%20heather%20on%20fire%22&hl=en&sa=X&ei=Hg9iT8OJOK-A0AX0nIWjCA&ved=0CDEQ6AEwAA#v=onepage&q=%22set%20the%20heather%20on%20fire%22&f=false
  [2]: http://idioms.thefreedictionary.com/set+the+world+on+fire
  [3]: https://english.stackexchange.com/questions/41326/