The flower seeds require a cold treatment to germinate. You can either sow them on the ground where you will be growing them permanently or sow the seeds in pots, and then bring the pots in after a month or so of freezing weather. The freezing will encourage them to germinate more easily. If you choose to sow the Christmas Rose flower seeds indoors, freeze the seeds for 3 - 6 weeks to break dormancy, then plant the flower seeds in starting medium. When the plant is around 2 inches tall, transplant to the permanent place. Helleborus Niger plants can take up to 3 years to flower when grown by seeds. Christmas Rose is a poisonous plant.