This text comes from The Scottish Minstrel (First Series), a historical songbook transcribed on Wikisource and reproduced from the pinned revision linked below.
O! Deck thy hair wi' the heather bell,
The heather bell alone:
Leave roses to the lowland maid,
The lowland maid alone.
I've seen thee wi' the gay, gay rose,
And wi' the heather bell.—
I love thee much with both, fair maid;
But wear the heather bell:
For the heather bell, the heather bell,
Which breathes the mountain air,
Is far more fit than roses gay,
To deck thy flowing hair.
Away, away, ye roses gay!
The heather bell for me;
Fair maiden, let me hear thee say,
The heather bell for me.
Then twine a wreath o' the heather bell,
The heather bell alone;
Nor rose nor lily twine ye there—
The leather bell alone.
For the heather bell, &c.