Sorry this is an old thread - just found it. In the UK, the native English bluebell (hyacinthoides non-scripta) is protected because it is under threat from the Spanish bluebell (hyacinthoides hispanica). The Spanish bluebell makes a better garden plant and was introduced to the UK some 300 years ago, but some have escaped into the wild and are cross-pollinating with the English bluebell.
I wrote an article about it if you are interested.