There are numerous variations, but here's one (though not my favorite):
[i]They buried Willie in the old church yard,
And Barbara there anigh him,
And out of his grave grew a red, red rose,
And out of hers, a briar.

They grew and grew in the old churchyard,
Till they couldn't grow no higher,
They lapped and tied in a true love's knot.
The rose ran around the briar.[/i]

~Barbara Allen (of course)