One fact--

Innisfree, whose name means "heather island" in Gaelic。 Heather is a kind flowering grass.

see http://www.gradesaver.com/poems-of-wb-yeats-the-rose/study-guide/summary-the-lake-isle-of-innisfree

我不反对想象， 但想象是个双刃剑， 有时过多的想象适得其反。 为蛇足者终失其酒即为一例。