Scrubby plants of the genus Erica– whcih may grow on a type of land called “heath“.  Heath and heather seem to have developed separately as words – the plant in England was called “ling” until the 1800s.  Hmmm.

• 03.007 a wide land the colour of heather
• 03.009 and others were half covered with moss or heather.
• 19.011 The wind’s in the tree-top, the wind’s in the heather;

“heather, n.” OED Online. Oxford University Press, June 2015. Web. 25 July 2015.