What is Blake's inspiration in writing the poem Sick Rose?

The rose symbolizes earthly, as opposed to spiritual, love, which becomes ill when infected with the materialism of the world. The rose’s bed of “crimson joy” may also be a sexual image, with the admittedly phallic worm representing either lust or jealousy. The worm has a “dark secret love” that destroys the rose’s life, suggesting something sinful or unmentionable.