It seems everybody has overlooked a certain oddity in the German language: Words with the ending -lein or -chen are treated as "it", (even Mädchen = girl). In some cases, "it" has the same pronoun as "he", as opposed to "she".

Thus, in the 3rd verse of Heidenröslein:

Röslein wehrte sich und stach,
Half IHN doch kein Weh und Ach,
Musst es eben leiden.

translates as follows:

Little rose defended herself and stung,
Crying and lamenting helped HER none,
Had to suffer it anyhow.

The rape motif is obbvious. There was no mention of blood in the original poem, but if there had been, it would have been hers, not his.

It's been 55 years since I learned the song at school. Didn't understand the meaning then, of course. I remember we translated "morgenschön" in the 1st verse as "sprinkled with morning dew".