"Poisonous to rodents and other wild animals, they were often planted in and around graveyards during Japan’s pre-cremation days to stop the dead being eaten. The beginning, perhaps, of their connection with death.
The name of the flower can also refer to ‘the other shore’; its bright colours said to guide souls into the afterlife. An aspect that presumably explains its use at funerals.
And if that wasn’t enough, another story is that red spider lilies bloom along the paths of departing lovers. Companions who for one reason or another are destined to never meet again."
-description of red Spider Lily meaning by Tokio Times