Seed pods take about six months to mature, at which time they turn brown and split open. Seeds are winged for wind dispersal and there may be more than 250 seeds on one flowerhead in a good year.
Sow seeds in a pot filled with a well-drained seed raising mix, cover with a fine layer of mix and water well. Transplant seedlings into a freely draining potting mix that does not contain any added nutrients and add some slow-release low phosphorus fertiliser several weeks later. Keep potted waratahs in partial shade, off the ground, for at least one year and make sure the roots are kept moist but not wet.