Blue bonnet or bluebonnet may refer to: 1  Blue Bonnet (brand) , a brand of margarine. 2  Bluebonnet (bird) an Australian parrot of the genus Northiella. 3  Bluebonnet (plant) , various lupin species.lue bonnet or bluebonnet may refer to: 1  Blue Bonnet (brand) , a brand of margarine. 2  Bluebonnet (bird) an Australian parrot of the genus Northiella. 3  Bluebonnet (plant) , various lupin species.