It's a pretty antiquated and uncommon turn of phrase - popularised if not actually coined in Walter Scott's 1818 novel Rob Roy. 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 (or maybe the also uncommon sets [one's] hair on fire, for things which only disturb/excite one or a relatively small number of people).

It's a pretty antiquated and uncommon turn of phrase - popularised if not actually coined in Walter Scott's 1818 novel Rob Roy. 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 (or maybe the also uncommon sets [one's] hair on fire, for things which only disturb/excite one or a relatively small number of people).