Cardinal flowers can be propagated by seed, division, or stem cuttings.
Seed propagation
- Collect the brown seed capsules in the fall.
- Place the capsules in a paper bag and shake to release the seeds.
- Store the seeds in a sealed container in the refrigerator for a couple of months.
- Sow the seeds thinly in a flat with a damp, fine peat mix.
- Keep the flats moist and under lights or in a greenhouse.
- Transplant seedlings into individual pots after 4 to 6 weeks.
Division propagation
- Dig up the entire colony in the fall.
- Cut the colony into sections.
- Replant each section 12 inches apart.
Stem cutting propagation
- Take cuttings that are between 4 and 6 inches in length with two nodes before the flowers open.
- Remove the lower leaf and half of the upper leaf.
- Dip cuttings in a rooting hormone.
- Place cuttings in a 50 sand:50 perlite (v/v) media.
- Water lightly and keep moist.
Cardinal flowers are short-lived perennials that self-sow easily. They are easy to grow and prefer moist soils in full sun to partial shade.